Discontinuous Reception for a Two-step Random Access Procedure

ABSTRACT

A wireless device receives one or more configuration parameters for a two-step random access channel (RACH) procedure. The wireless device transmits, based on the configuration parameters, a message, for the two-step RACH, comprising a preamble and a transport block. The wireless device receives, during a discontinuous reception (DRX) active time of a DRX operation of the wireless device, a response to the message. The DRX active time may be based on a time window for receiving the response to the message. The time window may start at least one symbol after a transmission occasion of the transport block.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/550,749, filed Dec. 14, 2021, which is a continuation ofInternational Application No. PCT/US2020/054229, filed Oct. 5, 2020,which claims the benefit of U.S. Provisional Application No. 62/910,257,filed Oct. 3, 2019, all of which are hereby incorporated by reference intheir entireties.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of several of the various embodiments of the present disclosureare described herein with reference to the drawings.

FIG. 1A and FIG. 1B illustrate example mobile communication networks inwhich embodiments of the present disclosure may be implemented.

FIG. 2A and FIG. 2B respectively illustrate a New Radio (NR) user planeand control plane protocol stack.

FIG. 3 illustrates an example of services provided between protocollayers of the NR user plane protocol stack of FIG. 2A.

FIG. 4A illustrates an example downlink data flow through the NR userplane protocol stack of FIG. 2A.

FIG. 4B illustrates an example format of a MAC subheader in a MAC PDU.

FIG. 5A and FIG. 5B respectively illustrate a mapping between logicalchannels, transport channels, and physical channels for the downlink anduplink.

FIG. 6 is an example diagram showing RRC state transitions of a UE.

FIG. 7 illustrates an example configuration of an NR frame into whichOFDM symbols are grouped.

FIG. 8 illustrates an example configuration of a slot in the time andfrequency domain for an NR carrier.

FIG. 9 illustrates an example of bandwidth adaptation using threeconfigured BWPs for an NR carrier.

FIG. 10A illustrates three carrier aggregation configurations with twocomponent carriers.

FIG. 10B illustrates an example of how aggregated cells may beconfigured into one or more PUCCH groups.

FIG. 11A illustrates an example of an SS/PBCH block structure andlocation.

FIG. 11B illustrates an example of CSI-RSs that are mapped in the timeand frequency domains.

FIG. 12A and FIG. 12B respectively illustrate examples of three downlinkand uplink beam management procedures.

FIG. 13A, FIG. 13B, and FIG. 13C respectively illustrate a four-stepcontention-based random access procedure, a two-step contention-freerandom access procedure, and another two-step random access procedure.

FIG. 14A illustrates an example of CORESET configurations for abandwidth part.

FIG. 14B illustrates an example of a CCE-to-REG mapping for DCItransmission on a CORESET and PDCCH processing.

FIG. 15 illustrates an example of a wireless device in communicationwith a base station.

FIG. 16A, FIG. 16B, FIG. 16C, and FIG. 16D illustrate example structuresfor uplink and downlink transmission.

FIG. 17A is an example of a PRACH occasion TDMed with a UL radioresources as per an aspect of an example embodiment of the presentdisclosure.

FIG. 17B is an example of a PRACH occasion FDMed with a UL radioresources as per an aspect of an example embodiment of the presentdisclosure.

FIG. 17C is an example of a PRACH occasion TDMed and FDMed with a ULradio resources as per an aspect of an example embodiment of the presentdisclosure.

FIG. 18 shows an example of ra-ssb-OccasionMaskIndex values as per anaspect of an example embodiment of the present disclosure.

FIG. 19A illustrates an RAR as per an aspect of an example embodiment ofthe present disclosure.

FIG. 19B illustrates a MAC subheader as per an aspect of an exampleembodiment of the present disclosure.

FIG. 19C illustrates an RAR as per an aspect of an example embodiment ofthe present disclosure.

FIG. 20 illustrates a MAC RAR format as per an aspect of an exampleembodiment of the present disclosure.

FIG. 21 illustrates an RAR format as per an aspect of an exampleembodiment of the present disclosure.

FIG. 22A illustrates an RAR format as per an aspect of an exampleembodiment of the present disclosure.

FIG. 22B illustrates an RAR format as per an aspect of an exampleembodiment of the present disclosure.

FIG. 23 is a diagram illustrating a two-step RA procedure as per anaspect of an example embodiment of the present disclosure.

FIG. 24A is a diagram of a two-step RA procedure as per an aspect of anexample embodiment of the present disclosure.

FIG. 24B is a diagram of a two-step RA procedure as per an aspect of anexample embodiment of the present disclosure.

FIG. 25 is a diagram showing an two-step RA procedure as per an aspectof an example embodiment of the present disclosure.

FIG. 26 illustrates a two-step RA procedure as per an aspect of anexample embodiment of the present disclosure.

FIG. 27 illustrates a two-step RA procedure as per an aspect of anexample embodiment of the present disclosure.

FIG. 28 illustrates a DRX operation as per an aspect of an exampleembodiment of the present disclosure.

FIG. 29A illustrates an active time of the DRX operation as per anaspect of an example embodiment of the present disclosure.

FIG. 29B illustrates an active time of the DRX operation as per anaspect of an example embodiment of the present disclosure.

FIG. 30A illustrates a DRX operation as per an aspect of an exampleembodiment of the present disclosure.

FIG. 30B illustrates a DRX operation as per an aspect of an exampleembodiment of the present disclosure.

FIG. 31 illustrates a DRX operation as per an aspect of an exampleembodiment of the present disclosure.

FIG. 32 illustrates a DRX operation as per an aspect of an exampleembodiment of the present disclosure.

FIG. 33 illustrates a DRX operation as per an aspect of an exampleembodiment of the present disclosure.

FIG. 34 illustrates a DRX operation as per an aspect of an exampleembodiment of the present disclosure.

FIG. 35 is a flow diagram as per an aspect of an example embodiment ofthe present disclosure.

FIG. 36 is a flow diagram as per an aspect of an example embodiment ofthe present disclosure.

DETAILED DESCRIPTION

In the present disclosure, various embodiments are presented as examplesof how the disclosed techniques may be implemented and/or how thedisclosed techniques may be practiced in environments and scenarios. Itwill be apparent to persons skilled in the relevant art that variouschanges in form and detail can be made therein without departing fromthe scope. In fact, after reading the description, it will be apparentto one skilled in the relevant art how to implement alternativeembodiments. The present embodiments should not be limited by any of thedescribed exemplary embodiments. The embodiments of the presentdisclosure will be described with reference to the accompanyingdrawings. Limitations, features, and/or elements from the disclosedexample embodiments may be combined to create further embodiments withinthe scope of the disclosure. Any figures which highlight thefunctionality and advantages, are presented for example purposes only.The disclosed architecture is sufficiently flexible and configurable,such that it may be utilized in ways other than that shown. For example,the actions listed in any flowchart may be re-ordered or only optionallyused in some embodiments.

Embodiments may be configured to operate as needed. The disclosedmechanism may be performed when certain criteria are met, for example,in a wireless device, a base station, a radio environment, a network, acombination of the above, and/or the like. Example criteria may bebased, at least in part, on for example, wireless device or network nodeconfigurations, traffic load, initial system set up, packet sizes,traffic characteristics, a combination of the above, and/or the like.When the one or more criteria are met, various example embodiments maybe applied. Therefore, it may be possible to implement exampleembodiments that selectively implement disclosed protocols.

A base station may communicate with a mix of wireless devices. Wirelessdevices and/or base stations may support multiple technologies, and/ormultiple releases of the same technology. Wireless devices may have somespecific capability(ies) depending on wireless device category and/orcapability(ies). When this disclosure refers to a base stationcommunicating with a plurality of wireless devices, this disclosure mayrefer to a subset of the total wireless devices in a coverage area. Thisdisclosure may refer to, for example, a plurality of wireless devices ofa given LTE or 5G release with a given capability and in a given sectorof the base station. The plurality of wireless devices in thisdisclosure may refer to a selected plurality of wireless devices, and/ora subset of total wireless devices in a coverage area which performaccording to disclosed methods, and/or the like. There may be aplurality of base stations or a plurality of wireless devices in acoverage area that may not comply with the disclosed methods, forexample, those wireless devices or base stations may perform based onolder releases of LTE or 5G technology.

In this disclosure, “a” and “an” and similar phrases are to beinterpreted as “at least one” and “one or more.” Similarly, any termthat ends with the suffix “(s)” is to be interpreted as “at least one”and “one or more.” In this disclosure, the term “may” is to beinterpreted as “may, for example.” In other words, the term “may” isindicative that the phrase following the term “may” is an example of oneof a multitude of suitable possibilities that may, or may not, beemployed by one or more of the various embodiments. The terms“comprises” and “consists of”, as used herein, enumerate one or morecomponents of the element being described. The term “comprises” isinterchangeable with “includes” and does not exclude unenumeratedcomponents from being included in the element being described. Bycontrast, “consists of” provides a complete enumeration of the one ormore components of the element being described. The term “based on”, asused herein, should be interpreted as “based at least in part on” ratherthan, for example, “based solely on”. The term “and/or” as used hereinrepresents any possible combination of enumerated elements. For example,“A, B, and/or C” may represent A; B; C; A and B; A and C; B and C; or A,B, and C.

If A and B are sets and every element of A is an element of B, A iscalled a subset of B. In this specification, only non-empty sets andsubsets are considered. For example, possible subsets of B={cell1,cell2} are: {cell1}, {cell2}, and {cell1, cell2}. The phrase “based on”(or equally “based at least on”) is indicative that the phrase followingthe term “based on” is an example of one of a multitude of suitablepossibilities that may, or may not, be employed to one or more of thevarious embodiments. The phrase “in response to” (or equally “inresponse at least to”) is indicative that the phrase following thephrase “in response to” is an example of one of a multitude of suitablepossibilities that may, or may not, be employed to one or more of thevarious embodiments. The phrase “depending on” (or equally “depending atleast to”) is indicative that the phrase following the phrase “dependingon” is an example of one of a multitude of suitable possibilities thatmay, or may not, be employed to one or more of the various embodiments.The phrase “employing/using” (or equally “employing/using at least”) isindicative that the phrase following the phrase “employing/using” is anexample of one of a multitude of suitable possibilities that may, or maynot, be employed to one or more of the various embodiments.

The term configured may relate to the capacity of a device whether thedevice is in an operational or non-operational state. Configured mayrefer to specific settings in a device that effect the operationalcharacteristics of the device whether the device is in an operational ornon-operational state. In other words, the hardware, software, firmware,registers, memory values, and/or the like may be “configured” within adevice, whether the device is in an operational or nonoperational state,to provide the device with specific characteristics. Terms such as “acontrol message to cause in a device” may mean that a control messagehas parameters that may be used to configure specific characteristics ormay be used to implement certain actions in the device, whether thedevice is in an operational or non-operational state.

In this disclosure, parameters (or equally called, fields, orInformation elements: IEs) may comprise one or more information objects,and an information object may comprise one or more other objects. Forexample, if parameter (IE) N comprises parameter (IE) M, and parameter(IE) M comprises parameter (IE) K, and parameter (IE) K comprisesparameter (information element) J. Then, for example, N comprises K, andN comprises J. In an example embodiment, when one or more messagescomprise a plurality of parameters, it implies that a parameter in theplurality of parameters is in at least one of the one or more messages,but does not have to be in each of the one or more messages.

Many features presented are described as being optional through the useof “may” or the use of parentheses. For the sake of brevity andlegibility, the present disclosure does not explicitly recite each andevery permutation that may be obtained by choosing from the set ofoptional features. The present disclosure is to be interpreted asexplicitly disclosing all such permutations. For example, a systemdescribed as having three optional features may be embodied in sevenways, namely with just one of the three possible features, with any twoof the three possible features or with three of the three possiblefeatures.

Many of the elements described in the disclosed embodiments may beimplemented as modules. A module is defined here as an element thatperforms a defined function and has a defined interface to otherelements. The modules described in this disclosure may be implemented inhardware, software in combination with hardware, firmware, wetware (e.g.hardware with a biological element) or a combination thereof, which maybe behaviorally equivalent. For example, modules may be implemented as asoftware routine written in a computer language configured to beexecuted by a hardware machine (such as C, C++, Fortran, Java, Basic,Matlab or the like) or a modeling/simulation program such as Simulink,Stateflow, GNU Octave, or Lab VIEWMathScript. It may be possible toimplement modules using physical hardware that incorporates discrete orprogrammable analog, digital and/or quantum hardware. Examples ofprogrammable hardware comprise: computers, microcontrollers,microprocessors, application-specific integrated circuits (ASICs); fieldprogrammable gate arrays (FPGAs); and complex programmable logic devices(CPLDs). Computers, microcontrollers and microprocessors are programmedusing languages such as assembly, C, C++ or the like. FPGAs, ASICs andCPLDs are often programmed using hardware description languages (HDL)such as VHSIC hardware description language (VHDL) or Verilog thatconfigure connections between internal hardware modules with lesserfunctionality on a programmable device. The mentioned technologies areoften used in combination to achieve the result of a functional module.

FIG. 1A illustrates an example of a mobile communication network 100 inwhich embodiments of the present disclosure may be implemented. Themobile communication network 100 may be, for example, a public landmobile network (PLMN) run by a network operator. As illustrated in FIG.1A, the mobile communication network 100 includes a core network (CN)102, a radio access network (RAN) 104, and a wireless device 106.

The CN 102 may provide the wireless device 106 with an interface to oneor more data networks (DNs), such as public DNs (e.g., the Internet),private DNs, and/or intra-operator DNs. As part of the interfacefunctionality, the CN 102 may set up end-to-end connections between thewireless device 106 and the one or more DNs, authenticate the wirelessdevice 106, and provide charging functionality.

The RAN 104 may connect the CN 102 to the wireless device 106 throughradio communications over an air interface. As part of the radiocommunications, the RAN 104 may provide scheduling, radio resourcemanagement, and retransmission protocols. The communication directionfrom the RAN 104 to the wireless device 106 over the air interface isknown as the downlink and the communication direction from the wirelessdevice 106 to the RAN 104 over the air interface is known as the uplink.Downlink transmissions may be separated from uplink transmissions usingfrequency division duplexing (FDD), time-division duplexing (TDD),and/or some combination of the two duplexing techniques.

The term wireless device may be used throughout this disclosure to referto and encompass any mobile device or fixed (non-mobile) device forwhich wireless communication is needed or usable. For example, awireless device may be a telephone, smart phone, tablet, computer,laptop, sensor, meter, wearable device, Internet of Things (IoT) device,vehicle road side unit (RSU), relay node, automobile, and/or anycombination thereof. The term wireless device encompasses otherterminology, including user equipment (UE), user terminal (UT), accessterminal (AT), mobile station, handset, wireless transmit and receiveunit (WTRU), and/or wireless communication device.

The RAN 104 may include one or more base stations (not shown). The termbase station may be used throughout this disclosure to refer to andencompass a Node B (associated with UMTS and/or 3G standards), anEvolved Node B (eNB, associated with E-UTRA and/or 4G standards), aremote radio head (RRH), a baseband processing unit coupled to one ormore RRHs, a repeater node or relay node used to extend the coveragearea of a donor node, a Next Generation Evolved Node B (ng-eNB), aGeneration Node B (gNB, associated with NR and/or 5G standards), anaccess point (AP, associated with, for example, WiFi or any othersuitable wireless communication standard), and/or any combinationthereof. A base station may comprise at least one gNB Central Unit(gNB-CU) and at least one a gNB Distributed Unit (gNB-DU).

A base station included in the RAN 104 may include one or more sets ofantennas for communicating with the wireless device 106 over the airinterface. For example, one or more of the base stations may includethree sets of antennas to respectively control three cells (or sectors).The size of a cell may be determined by a range at which a receiver(e.g., a base station receiver) can successfully receive thetransmissions from a transmitter (e.g., a wireless device transmitter)operating in the cell. Together, the cells of the base stations mayprovide radio coverage to the wireless device 106 over a wide geographicarea to support wireless device mobility.

In addition to three-sector sites, other implementations of basestations are possible. For example, one or more of the base stations inthe RAN 104 may be implemented as a sectored site with more or less thanthree sectors. One or more of the base stations in the RAN 104 may beimplemented as an access point, as a baseband processing unit coupled toseveral remote radio heads (RRHs), and/or as a repeater or relay nodeused to extend the coverage area of a donor node. A baseband processingunit coupled to RRHs may be part of a centralized or cloud RANarchitecture, where the baseband processing unit may be eithercentralized in a pool of baseband processing units or virtualized. Arepeater node may amplify and rebroadcast a radio signal received from adonor node. A relay node may perform the same/similar functions as arepeater node but may decode the radio signal received from the donornode to remove noise before amplifying and rebroadcasting the radiosignal.

The RAN 104 may be deployed as a homogenous network of macrocell basestations that have similar antenna patterns and similar high-leveltransmit powers. The RAN 104 may be deployed as a heterogeneous network.In heterogeneous networks, small cell base stations may be used toprovide small coverage areas, for example, coverage areas that overlapwith the comparatively larger coverage areas provided by macrocell basestations. The small coverage areas may be provided in areas with highdata traffic (or so-called “hotspots”) or in areas with weak macrocellcoverage. Examples of small cell base stations include, in order ofdecreasing coverage area, microcell base stations, picocell basestations, and femtocell base stations or home base stations.

The Third-Generation Partnership Project (3GPP) was formed in 1998 toprovide global standardization of specifications for mobilecommunication networks similar to the mobile communication network 100in FIG. 1A. To date, 3GPP has produced specifications for threegenerations of mobile networks: a third generation (3G) network known asUniversal Mobile Telecommunications System (UMTS), a fourth generation(4G) network known as Long-Term Evolution (LTE), and a fifth generation(5G) network known as 5G System (5GS). Embodiments of the presentdisclosure are described with reference to the RAN of a 3GPP 5G network,referred to as next-generation RAN (NG-RAN). Embodiments may beapplicable to RANs of other mobile communication networks, such as theRAN 104 in FIG. 1A, the RANs of earlier 3G and 4G networks, and those offuture networks yet to be specified (e.g., a 3GPP 6G network). NG-RANimplements 5G radio access technology known as New Radio (NR) and may beprovisioned to implement 4G radio access technology or other radioaccess technologies, including non-3GPP radio access technologies.

FIG. 1B illustrates another example mobile communication network 150 inwhich embodiments of the present disclosure may be implemented. Mobilecommunication network 150 may be, for example, a PLMN run by a networkoperator. As illustrated in FIG. 1B, mobile communication network 150includes a 5G core network (5G-CN) 152, an NG-RAN 154, and UEs 156A and156B (collectively UEs 156). These components may be implemented andoperate in the same or similar manner as corresponding componentsdescribed with respect to FIG. 1A.

The 5G-CN 152 provides the UEs 156 with an interface to one or more DNs,such as public DNs (e.g., the Internet), private DNs, and/orintra-operator DNs. As part of the interface functionality, the 5G-CN152 may set up end-to-end connections between the UEs 156 and the one ormore DNs, authenticate the UEs 156, and provide charging functionality.Compared to the CN of a 3GPP 4G network, the basis of the 5G-CN 152 maybe a service-based architecture. This means that the architecture of thenodes making up the 5G-CN 152 may be defined as network functions thatoffer services via interfaces to other network functions. The networkfunctions of the 5G-CN 152 may be implemented in several ways, includingas network elements on dedicated or shared hardware, as softwareinstances running on dedicated or shared hardware, or as virtualizedfunctions instantiated on a platform (e.g., a cloud-based platform).

As illustrated in FIG. 1B, the 5G-CN 152 includes an Access and MobilityManagement Function (AMF) 158A and a User Plane Function (UPF) 158B,which are shown as one component AMF/UPF 158 in FIG. 1B for ease ofillustration. The UPF 158B may serve as a gateway between the NG-RAN 154and the one or more DNs. The UPF 158B may perform functions such aspacket routing and forwarding, packet inspection and user plane policyrule enforcement, traffic usage reporting, uplink classification tosupport routing of traffic flows to the one or more DNs, quality ofservice (QoS) handling for the user plane (e.g., packet filtering,gating, uplink/downlink rate enforcement, and uplink trafficverification), downlink packet buffering, and downlink data notificationtriggering. The UPF 158B may serve as an anchor point forintra-/inter-Radio Access Technology (RAT) mobility, an externalprotocol (or packet) data unit (PDU) session point of interconnect tothe one or more DNs, and/or a branching point to support a multi-homedPDU session. The UEs 156 may be configured to receive services through aPDU session, which is a logical connection between a UE and a DN.

The AMF 158A may perform functions such as Non-Access Stratum (NAS)signaling termination, NAS signaling security, Access Stratum (AS)security control, inter-CN node signaling for mobility between 3GPPaccess networks, idle mode UE reachability (e.g., control and executionof paging retransmission), registration area management, intra-systemand inter-system mobility support, access authentication, accessauthorization including checking of roaming rights, mobility managementcontrol (subscription and policies), network slicing support, and/orsession management function (SMF) selection. NAS may refer to thefunctionality operating between a CN and a UE, and AS may refer to thefunctionality operating between the UE and a RAN.

The 5G-CN 152 may include one or more additional network functions thatare not shown in FIG. 1B for the sake of clarity. For example, the 5G-CN152 may include one or more of a Session Management Function (SMF), anNR Repository Function (NRF), a Policy Control Function (PCF), a NetworkExposure Function (NEF), a Unified Data Management (UDM), an ApplicationFunction (AF), and/or an Authentication Server Function (AUSF).

The NG-RAN 154 may connect the 5G-CN 152 to the UEs 156 through radiocommunications over the air interface. The NG-RAN 154 may include one ormore gNBs, illustrated as gNB 160A and gNB 160B (collectively gNBs 160)and/or one or more ng-eNB s, illustrated as ng-eNB 162A and ng-eNB 162B(collectively ng-eNB s 162). The gNBs 160 and ng-eNB s 162 may be moregenerically referred to as base stations. The gNBs 160 and ng-eNBs 162may include one or more sets of antennas for communicating with the UEs156 over an air interface. For example, one or more of the gNBs 160and/or one or more of the ng-eNB s 162 may include three sets ofantennas to respectively control three cells (or sectors). Together, thecells of the gNBs 160 and the ng-eNBs 162 may provide radio coverage tothe UEs 156 over a wide geographic area to support UE mobility.

As shown in FIG. 1B, the gNBs 160 and/or the ng-eNBs 162 may beconnected to the 5G-CN 152 by means of an NG interface and to other basestations by an Xn interface. The NG and Xn interfaces may be establishedusing direct physical connections and/or indirect connections over anunderlying transport network, such as an internet protocol (IP)transport network. The gNBs 160 and/or the ng-eNBs 162 may be connectedto the UEs 156 by means of a Uu interface. For example, as illustratedin FIG. 1B, gNB 160A may be connected to the UE 156A by means of a Uuinterface. The NG, Xn, and Uu interfaces are associated with a protocolstack. The protocol stacks associated with the interfaces may be used bythe network elements in FIG. 1B to exchange data and signaling messagesand may include two planes: a user plane and a control plane. The userplane may handle data of interest to a user. The control plane mayhandle signaling messages of interest to the network elements.

The gNBs 160 and/or the ng-eNBs 162 may be connected to one or moreAMF/UPF functions of the 5G-CN 152, such as the AMF/UPF 158, by means ofone or more NG interfaces. For example, the gNB 160A may be connected tothe UPF 158B of the AMF/UPF 158 by means of an NG-User plane (NG-U)interface. The NG-U interface may provide delivery (e.g., non-guaranteeddelivery) of user plane PDUs between the gNB 160A and the UPF 158B. ThegNB 160A may be connected to the AMF 158A by means of an NG-Controlplane (NG-C) interface. The NG-C interface may provide, for example, NGinterface management, UE context management, UE mobility management,transport of NAS messages, paging, PDU session management, andconfiguration transfer and/or warning message transmission.

The gNBs 160 may provide NR user plane and control plane protocolterminations towards the UEs 156 over the Uu interface. For example, thegNB 160A may provide NR user plane and control plane protocolterminations toward the UE 156A over a Uu interface associated with afirst protocol stack. The ng-eNBs 162 may provide Evolved UMTSTerrestrial Radio Access (E-UTRA) user plane and control plane protocolterminations towards the UEs 156 over a Uu interface, where E-UTRArefers to the 3GPP 4G radio-access technology. For example, the ng-eNB162B may provide E-UTRA user plane and control plane protocolterminations towards the UE 156B over a Uu interface associated with asecond protocol stack.

The 5G-CN 152 was described as being configured to handle NR and 4Gradio accesses. It will be appreciated by one of ordinary skill in theart that it may be possible for NR to connect to a 4G core network in amode known as “non-standalone operation.” In non-standalone operation, a4G core network is used to provide (or at least support) control-planefunctionality (e.g., initial access, mobility, and paging). Althoughonly one AMF/UPF 158 is shown in FIG. 1B, one gNB or ng-eNB may beconnected to multiple AMF/UPF nodes to provide redundancy and/or to loadshare across the multiple AMF/UPF nodes.

As discussed, an interface (e.g., Uu, Xn, and NG interfaces) between thenetwork elements in FIG. 1B may be associated with a protocol stack thatthe network elements use to exchange data and signaling messages. Aprotocol stack may include two planes: a user plane and a control plane.The user plane may handle data of interest to a user, and the controlplane may handle signaling messages of interest to the network elements.

FIG. 2A and FIG. 2B respectively illustrate examples of NR user planeand NR control plane protocol stacks for the Uu interface that liesbetween a UE 210 and a gNB 220. The protocol stacks illustrated in FIG.2A and FIG. 2B may be the same or similar to those used for the Uuinterface between, for example, the UE 156A and the gNB 160A shown inFIG. 1B.

FIG. 2A illustrates a NR user plane protocol stack comprising fivelayers implemented in the UE 210 and the gNB 220. At the bottom of theprotocol stack, physical layers (PHYs) 211 and 221 may provide transportservices to the higher layers of the protocol stack and may correspondto layer 1 of the Open Systems Interconnection (OSI) model. The nextfour protocols above PHYs 211 and 221 comprise media access controllayers (MACs) 212 and 222, radio link control layers (RLCs) 213 and 223,packet data convergence protocol layers (PDCPs) 214 and 224, and servicedata application protocol layers (SDAPs) 215 and 225. Together, thesefour protocols may make up layer 2, or the data link layer, of the OSImodel.

FIG. 3 illustrates an example of services provided between protocollayers of the NR user plane protocol stack. Starting from the top ofFIG. 2A and FIG. 3 , the SDAPs 215 and 225 may perform QoS flowhandling. The UE 210 may receive services through a PDU session, whichmay be a logical connection between the UE 210 and a DN. The PDU sessionmay have one or more QoS flows. A UPF of a CN (e.g., the UPF 158B) maymap IP packets to the one or more QoS flows of the PDU session based onQoS requirements (e.g., in terms of delay, data rate, and/or errorrate). The SDAPs 215 and 225 may perform mapping/de-mapping between theone or more QoS flows and one or more data radio bearers. Themapping/de-mapping between the QoS flows and the data radio bearers maybe determined by the SDAP 225 at the gNB 220. The SDAP 215 at the UE 210may be informed of the mapping between the QoS flows and the data radiobearers through reflective mapping or control signaling received fromthe gNB 220. For reflective mapping, the SDAP 225 at the gNB 220 maymark the downlink packets with a QoS flow indicator (QFI), which may beobserved by the SDAP 215 at the UE 210 to determine themapping/de-mapping between the QoS flows and the data radio bearers.

The PDCPs 214 and 224 may perform header compression/decompression toreduce the amount of data that needs to be transmitted over the airinterface, ciphering/deciphering to prevent unauthorized decoding ofdata transmitted over the air interface, and integrity protection (toensure control messages originate from intended sources. The PDCPs 214and 224 may perform retransmissions of undelivered packets, in-sequencedelivery and reordering of packets, and removal of packets received induplicate due to, for example, an intra-gNB handover. The PDCPs 214 and224 may perform packet duplication to improve the likelihood of thepacket being received and, at the receiver, remove any duplicatepackets. Packet duplication may be useful for services that require highreliability.

Although not shown in FIG. 3 , PDCPs 214 and 224 may performmapping/de-mapping between a split radio bearer and RLC channels in adual connectivity scenario. Dual connectivity is a technique that allowsa UE to connect to two cells or, more generally, two cell groups: amaster cell group (MCG) and a secondary cell group (SCG). A split beareris when a single radio bearer, such as one of the radio bearers providedby the PDCPs 214 and 224 as a service to the SDAPs 215 and 225, ishandled by cell groups in dual connectivity. The PDCPs 214 and 224 maymap/de-map the split radio bearer between RLC channels belonging to cellgroups.

The RLCs 213 and 223 may perform segmentation, retransmission throughAutomatic Repeat Request (ARQ), and removal of duplicate data unitsreceived from MACs 212 and 222, respectively. The RLCs 213 and 223 maysupport three transmission modes: transparent mode (TM); unacknowledgedmode (UM); and acknowledged mode (AM). Based on the transmission mode anRLC is operating, the RLC may perform one or more of the notedfunctions. The RLC configuration may be per logical channel with nodependency on numerologies and/or Transmission Time Interval (TTI)durations. As shown in FIG. 3 , the RLCs 213 and 223 may provide RLCchannels as a service to PDCPs 214 and 224, respectively.

The MACs 212 and 222 may perform multiplexing/demultiplexing of logicalchannels and/or mapping between logical channels and transport channels.The multiplexing/demultiplexing may include multiplexing/demultiplexingof data units, belonging to the one or more logical channels, into/fromTransport Blocks (TBs) delivered to/from the PHYs 211 and 221. The MAC222 may be configured to perform scheduling, scheduling informationreporting, and priority handling between UEs by means of dynamicscheduling. Scheduling may be performed in the gNB 220 (at the MAC 222)for downlink and uplink. The MACs 212 and 222 may be configured toperform error correction through Hybrid Automatic Repeat Request (HARQ)(e.g., one HARQ entity per carrier in case of Carrier Aggregation (CA)),priority handling between logical channels of the UE 210 by means oflogical channel prioritization, and/or padding. The MACs 212 and 222 maysupport one or more numerologies and/or transmission timings. In anexample, mapping restrictions in a logical channel prioritization maycontrol which numerology and/or transmission timing a logical channelmay use. As shown in FIG. 3 , the MACs 212 and 222 may provide logicalchannels as a service to the RLCs 213 and 223.

The PHYs 211 and 221 may perform mapping of transport channels tophysical channels and digital and analog signal processing functions forsending and receiving information over the air interface. These digitaland analog signal processing functions may include, for example,coding/decoding and modulation/demodulation. The PHYs 211 and 221 mayperform multi-antenna mapping. As shown in FIG. 3 , the PHYs 211 and 221may provide one or more transport channels as a service to the MACs 212and 222.

FIG. 4A illustrates an example downlink data flow through the NR userplane protocol stack. FIG. 4A illustrates a downlink data flow of threeIP packets (n, n+1, and m) through the NR user plane protocol stack togenerate two TBs at the gNB 220. An uplink data flow through the NR userplane protocol stack may be similar to the downlink data flow depictedin FIG. 4A.

The downlink data flow of FIG. 4A begins when SDAP 225 receives thethree IP packets from one or more QoS flows and maps the three packetsto radio bearers. In FIG. 4A, the SDAP 225 maps IP packets n and n+1 toa first radio bearer 402 and maps IP packet m to a second radio bearer404. An SDAP header (labeled with an “H” in FIG. 4A) is added to an IPpacket. The data unit from/to a higher protocol layer is referred to asa service data unit (SDU) of the lower protocol layer and the data unitto/from a lower protocol layer is referred to as a protocol data unit(PDU) of the higher protocol layer. As shown in FIG. 4A, the data unitfrom the SDAP 225 is an SDU of lower protocol layer PDCP 224 and is aPDU of the SDAP 225.

The remaining protocol layers in FIG. 4A may perform their associatedfunctionality (e.g., with respect to FIG. 3 ), add correspondingheaders, and forward their respective outputs to the next lower layer.For example, the PDCP 224 may perform IP-header compression andciphering and forward its output to the RLC 223. The RLC 223 mayoptionally perform segmentation (e.g., as shown for IP packet m in FIG.4A) and forward its output to the MAC 222. The MAC 222 may multiplex anumber of RLC PDUs and may attach a MAC subheader to an RLC PDU to forma transport block. In NR, the MAC subheaders may be distributed acrossthe MAC PDU, as illustrated in FIG. 4A. In LTE, the MAC subheaders maybe entirely located at the beginning of the MAC PDU. The NR MAC PDUstructure may reduce processing time and associated latency because theMAC PDU subheaders may be computed before the full MAC PDU is assembled.

FIG. 4B illustrates an example format of a MAC subheader in a MAC PDU.The MAC subheader includes: an SDU length field for indicating thelength (e.g., in bytes) of the MAC SDU to which the MAC subheadercorresponds; a logical channel identifier (LCID) field for identifyingthe logical channel from which the MAC SDU originated to aid in thedemultiplexing process; a flag (F) for indicating the size of the SDUlength field; and a reserved bit (R) field for future use.

FIG. 4B further illustrates MAC control elements (CEs) inserted into theMAC PDU by a MAC, such as MAC 223 or MAC 222. For example, FIG. 4Billustrates two MAC CEs inserted into the MAC PDU. MAC CEs may beinserted at the beginning of a MAC PDU for downlink transmissions (asshown in FIG. 4B) and at the end of a MAC PDU for uplink transmissions.MAC CEs may be used for in-band control signaling. Example MAC CEsinclude: scheduling-related MAC CEs, such as buffer status reports andpower headroom reports; activation/deactivation MAC CEs, such as thosefor activation/deactivation of PDCP duplication detection, channel stateinformation (CSI) reporting, sounding reference signal (SRS)transmission, and prior configured components; discontinuous reception(DRX) related MAC CEs; timing advance MAC CEs; and random access relatedMAC CEs. A MAC CE may be preceded by a MAC subheader with a similarformat as described for MAC SDUs and may be identified with a reservedvalue in the LCID field that indicates the type of control informationincluded in the MAC CE.

Before describing the NR control plane protocol stack, logical channels,transport channels, and physical channels are first described as well asa mapping between the channel types. One or more of the channels may beused to carry out functions associated with the NR control planeprotocol stack described later below.

FIG. 5A and FIG. 5B illustrate, for downlink and uplink respectively, amapping between logical channels, transport channels, and physicalchannels. Information is passed through channels between the RLC, theMAC, and the PHY of the NR protocol stack. A logical channel may be usedbetween the RLC and the MAC and may be classified as a control channelthat carries control and configuration information in the NR controlplane or as a traffic channel that carries data in the NR user plane. Alogical channel may be classified as a dedicated logical channel that isdedicated to a specific UE or as a common logical channel that may beused by more than one UE. A logical channel may also be defined by thetype of information it carries. The set of logical channels defined byNR include, for example:

-   -   a paging control channel (PCCH) for carrying paging messages        used to page a UE whose location is not known to the network on        a cell level;    -   a broadcast control channel (BCCH) for carrying system        information messages in the form of a master information block        (MIB) and several system information blocks (SIBs), wherein the        system information messages may be used by the UEs to obtain        information about how a cell is configured and how to operate        within the cell;    -   a common control channel (CCCH) for carrying control messages        together with random access;    -   a dedicated control channel (DCCH) for carrying control messages        to/from a specific the UE to configure the UE; and    -   a dedicated traffic channel (DTCH) for carrying user data        to/from a specific the UE.

Transport channels are used between the MAC and PHY layers and may bedefined by how the information they carry is transmitted over the airinterface. The set of transport channels defined by NR include, forexample:

-   -   a paging channel (PCH) for carrying paging messages that        originated from the PCCH;    -   a broadcast channel (BCH) for carrying the MIB from the BCCH;    -   a downlink shared channel (DL-SCH) for carrying downlink data        and signaling messages, including the SIBs from the BCCH;    -   an uplink shared channel (UL-SCH) for carrying uplink data and        signaling messages; and    -   a random access channel (RACH) for allowing a UE to contact the        network without any prior scheduling.

The PHY may use physical channels to pass information between processinglevels of the PHY. A physical channel may have an associated set oftime-frequency resources for carrying the information of one or moretransport channels. The PHY may generate control information to supportthe low-level operation of the PHY and provide the control informationto the lower levels of the PHY via physical control channels, known asL1/L2 control channels. The set of physical channels and physicalcontrol channels defined by NR include, for example:

-   -   a physical broadcast channel (PBCH) for carrying the MIB from        the BCH;    -   a physical downlink shared channel (PDSCH) for carrying downlink        data and signaling messages from the DL-SCH, as well as paging        messages from the PCH;    -   a physical downlink control channel (PDCCH) for carrying        downlink control information (DCI), which may include downlink        scheduling commands, uplink scheduling grants, and uplink power        control commands;    -   a physical uplink shared channel (PUSCH) for carrying uplink        data and signaling messages from the UL-SCH and in some        instances uplink control information (UCI) as described below;    -   a physical uplink control channel (PUCCH) for carrying UCI,        which may include HARQ acknowledgments, channel quality        indicators (CQI), pre-coding matrix indicators (PMI), rank        indicators (RI), and scheduling requests (SR); and    -   a physical random access channel (PRACH) for random access.

Similar to the physical control channels, the physical layer generatesphysical signals to support the low-level operation of the physicallayer. As shown in FIG. 5A and FIG. 5B, the physical layer signalsdefined by NR include: primary synchronization signals (PSS), secondarysynchronization signals (SSS), channel state information referencesignals (CSI-RS), demodulation reference signals (DMRS), soundingreference signals (SRS), and phase-tracking reference signals (PT-RS).These physical layer signals will be described in greater detail below.

FIG. 2B illustrates an example NR control plane protocol stack. As shownin FIG. 2B, the NR control plane protocol stack may use the same/similarfirst four protocol layers as the example NR user plane protocol stack.These four protocol layers include the PHYs 211 and 221, the MACs 212and 222, the RLCs 213 and 223, and the PDCPs 214 and 224. Instead ofhaving the SDAPs 215 and 225 at the top of the stack as in the NR userplane protocol stack, the NR control plane stack has radio resourcecontrols (RRCs) 216 and 226 and NAS protocols 217 and 237 at the top ofthe NR control plane protocol stack.

The NAS protocols 217 and 237 may provide control plane functionalitybetween the UE 210 and the AMF 230 (e.g., the AMF 158A) or, moregenerally, between the UE 210 and the CN. The NAS protocols 217 and 237may provide control plane functionality between the UE 210 and the AMF230 via signaling messages, referred to as NAS messages. There is nodirect path between the UE 210 and the AMF 230 through which the NASmessages can be transported. The NAS messages may be transported usingthe AS of the Uu and NG interfaces. NAS protocols 217 and 237 mayprovide control plane functionality such as authentication, security,connection setup, mobility management, and session management.

The RRCs 216 and 226 may provide control plane functionality between theUE 210 and the gNB 220 or, more generally, between the UE 210 and theRAN. The RRCs 216 and 226 may provide control plane functionalitybetween the UE 210 and the gNB 220 via signaling messages, referred toas RRC messages. RRC messages may be transmitted between the UE 210 andthe RAN using signaling radio bearers and the same/similar PDCP, RLC,MAC, and PHY protocol layers. The MAC may multiplex control-plane anduser-plane data into the same transport block (TB). The RRCs 216 and 226may provide control plane functionality such as: broadcast of systeminformation related to AS and NAS; paging initiated by the CN or theRAN; establishment, maintenance and release of an RRC connection betweenthe UE 210 and the RAN; security functions including key management;establishment, configuration, maintenance and release of signaling radiobearers and data radio bearers; mobility functions; QoS managementfunctions; the UE measurement reporting and control of the reporting;detection of and recovery from radio link failure (RLF); and/or NASmessage transfer. As part of establishing an RRC connection, RRCs 216and 226 may establish an RRC context, which may involve configuringparameters for communication between the UE 210 and the RAN.

FIG. 6 is an example diagram showing RRC state transitions of a UE. TheUE may be the same or similar to the wireless device 106 depicted inFIG. 1A, the UE 210 depicted in FIG. 2A and FIG. 2B, or any otherwireless device described in the present disclosure. As illustrated inFIG. 6 , a UE may be in at least one of three RRC states: RRC connected602 (e.g., RRC_CONNECTED), RRC idle 604 (e.g., RRC_IDLE), and RRCinactive 606 (e.g., RRC_INACTIVE).

In RRC connected 602, the UE has an established RRC context and may haveat least one RRC connection with a base station. The base station may besimilar to one of the one or more base stations included in the RAN 104depicted in FIG. 1A, one of the gNBs 160 or ng-eNBs 162 depicted in FIG.1B, the gNB 220 depicted in FIG. 2A and FIG. 2B, or any other basestation described in the present disclosure. The base station with whichthe UE is connected may have the RRC context for the UE. The RRCcontext, referred to as the UE context, may comprise parameters forcommunication between the UE and the base station. These parameters mayinclude, for example: one or more AS contexts; one or more radio linkconfiguration parameters; bearer configuration information (e.g.,relating to a data radio bearer, signaling radio bearer, logicalchannel, QoS flow, and/or PDU session); security information; and/orPHY, MAC, RLC, PDCP, and/or SDAP layer configuration information. Whilein RRC connected 602, mobility of the UE may be managed by the RAN(e.g., the RAN 104 or the NG-RAN 154). The UE may measure the signallevels (e.g., reference signal levels) from a serving cell andneighboring cells and report these measurements to the base stationcurrently serving the UE. The UE's serving base station may request ahandover to a cell of one of the neighboring base stations based on thereported measurements. The RRC state may transition from RRC connected602 to RRC idle 604 through a connection release procedure 608 or to RRCinactive 606 through a connection inactivation procedure 610.

In RRC idle 604, an RRC context may not be established for the UE. InRRC idle 604, the UE may not have an RRC connection with the basestation. While in RRC idle 604, the UE may be in a sleep state for themajority of the time (e.g., to conserve battery power). The UE may wakeup periodically (e.g., once in every discontinuous reception cycle) tomonitor for paging messages from the RAN. Mobility of the UE may bemanaged by the UE through a procedure known as cell reselection. The RRCstate may transition from RRC idle 604 to RRC connected 602 through aconnection establishment procedure 612, which may involve a randomaccess procedure as discussed in greater detail below.

In RRC inactive 606, the RRC context previously established ismaintained in the UE and the base station. This allows for a fasttransition to RRC connected 602 with reduced signaling overhead ascompared to the transition from RRC idle 604 to RRC connected 602. Whilein RRC inactive 606, the UE may be in a sleep state and mobility of theUE may be managed by the UE through cell reselection. The RRC state maytransition from RRC inactive 606 to RRC connected 602 through aconnection resume procedure 614 or to RRC idle 604 though a connectionrelease procedure 616 that may be the same as or similar to connectionrelease procedure 608.

An RRC state may be associated with a mobility management mechanism. InRRC idle 604 and RRC inactive 606, mobility is managed by the UE throughcell reselection. The purpose of mobility management in RRC idle 604 andRRC inactive 606 is to allow the network to be able to notify the UE ofan event via a paging message without having to broadcast the pagingmessage over the entire mobile communications network. The mobilitymanagement mechanism used in RRC idle 604 and RRC inactive 606 may allowthe network to track the UE on a cell-group level so that the pagingmessage may be broadcast over the cells of the cell group that the UEcurrently resides within instead of the entire mobile communicationnetwork. The mobility management mechanisms for RRC idle 604 and RRCinactive 606 track the UE on a cell-group level. They may do so usingdifferent granularities of grouping. For example, there may be threelevels of cell-grouping granularity: individual cells; cells within aRAN area identified by a RAN area identifier (RAI); and cells within agroup of RAN areas, referred to as a tracking area and identified by atracking area identifier (TAI).

Tracking areas may be used to track the UE at the CN level. The CN(e.g., the CN 102 or the 5G-CN 152) may provide the UE with a list ofTAIs associated with a UE registration area. If the UE moves, throughcell reselection, to a cell associated with a TAI not included in thelist of TAIs associated with the UE registration area, the UE mayperform a registration update with the CN to allow the CN to update theUE's location and provide the UE with a new the UE registration area.

RAN areas may be used to track the UE at the RAN level. For a UE in RRCinactive 606 state, the UE may be assigned a RAN notification area. ARAN notification area may comprise one or more cell identities, a listof RAIs, or a list of TAIs. In an example, a base station may belong toone or more RAN notification areas. In an example, a cell may belong toone or more RAN notification areas. If the UE moves, through cellreselection, to a cell not included in the RAN notification areaassigned to the UE, the UE may perform a notification area update withthe RAN to update the UE's RAN notification area.

A base station storing an RRC context for a UE or a last serving basestation of the UE may be referred to as an anchor base station. Ananchor base station may maintain an RRC context for the UE at leastduring a period of time that the UE stays in a RAN notification area ofthe anchor base station and/or during a period of time that the UE staysin RRC inactive 606.

A gNB, such as gNBs 160 in FIG. 1B, may be split in two parts: a centralunit (gNB-CU), and one or more distributed units (gNB-DU). A gNB-CU maybe coupled to one or more gNB-DUs using an F1 interface. The gNB-CU maycomprise the RRC, the PDCP, and the SDAP. A gNB-DU may comprise the RLC,the MAC, and the PHY.

In NR, the physical signals and physical channels (discussed withrespect to FIG. 5A and FIG. 5B) may be mapped onto orthogonal frequencydivisional multiplexing (OFDM) symbols. OFDM is a multicarriercommunication scheme that transmits data over F orthogonal subcarriers(or tones). Before transmission, the data may be mapped to a series ofcomplex symbols (e.g., M-quadrature amplitude modulation (M-QAM) orM-phase shift keying (M-PSK) symbols), referred to as source symbols,and divided into F parallel symbol streams. The F parallel symbolstreams may be treated as though they are in the frequency domain andused as inputs to an Inverse Fast Fourier Transform (IFFT) block thattransforms them into the time domain. The IFFT block may take in Fsource symbols at a time, one from each of the F parallel symbolstreams, and use each source symbol to modulate the amplitude and phaseof one of F sinusoidal basis functions that correspond to the Forthogonal subcarriers. The output of the IFFT block may be Ftime-domain samples that represent the summation of the F orthogonalsubcarriers. The F time-domain samples may form a single OFDM symbol.After some processing (e.g., addition of a cyclic prefix) andup-conversion, an OFDM symbol provided by the IFFT block may betransmitted over the air interface on a carrier frequency. The Fparallel symbol streams may be mixed using an FFT block before beingprocessed by the IFFT block. This operation produces Discrete FourierTransform (DFT)-precoded OFDM symbols and may be used by UEs in theuplink to reduce the peak to average power ratio (PAPR). Inverseprocessing may be performed on the OFDM symbol at a receiver using anFFT block to recover the data mapped to the source symbols.

FIG. 7 illustrates an example configuration of an NR frame into whichOFDM symbols are grouped. An NR frame may be identified by a systemframe number (SFN). The SFN may repeat with a period of 1024 frames. Asillustrated, one NR frame may be 10 milliseconds (ms) in duration andmay include 10 subframes that are 1 ms in duration. A subframe may bedivided into slots that include, for example, 14 OFDM symbols per slot.

The duration of a slot may depend on the numerology used for the OFDMsymbols of the slot. In NR, a flexible numerology is supported toaccommodate different cell deployments (e.g., cells with carrierfrequencies below 1 GHz up to cells with carrier frequencies in themm-wave range). A numerology may be defined in terms of subcarrierspacing and cyclic prefix duration. For a numerology in NR, subcarrierspacings may be scaled up by powers of two from a baseline subcarrierspacing of 15 kHz, and cyclic prefix durations may be scaled down bypowers of two from a baseline cyclic prefix duration of 4.7 μs. Forexample, NR defines numerologies with the following subcarrierspacing/cyclic prefix duration combinations: 15 kHz/4.7 μs; 30 kHz/2.3μs; 60 kHz/1.2 μs; 120 kHz/0.59 μs; and 240 kHz/0.29 μs.

A slot may have a fixed number of OFDM symbols (e.g., 14 OFDM symbols).A numerology with a higher subcarrier spacing has a shorter slotduration and, correspondingly, more slots per subframe. FIG. 7illustrates this numerology-dependent slot duration andslots-per-subframe transmission structure (the numerology with asubcarrier spacing of 240 kHz is not shown in FIG. 7 for ease ofillustration). A subframe in NR may be used as a numerology-independenttime reference, while a slot may be used as the unit upon which uplinkand downlink transmissions are scheduled. To support low latency,scheduling in NR may be decoupled from the slot duration and start atany OFDM symbol and last for as many symbols as needed for atransmission. These partial slot transmissions may be referred to asmini-slot or subslot transmissions.

FIG. 8 illustrates an example configuration of a slot in the time andfrequency domain for an NR carrier. The slot includes resource elements(REs) and resource blocks (RBs). An RE is the smallest physical resourcein NR. An RE spans one OFDM symbol in the time domain by one subcarrierin the frequency domain as shown in FIG. 8 . An RB spans twelveconsecutive REs in the frequency domain as shown in FIG. 8 . An NRcarrier may be limited to a width of 275 RBs or 275×12=3300 subcarriers.Such a limitation, if used, may limit the NR carrier to 50, 100, 200,and 400 MHz for subcarrier spacings of 15, 30, 60, and 120 kHz,respectively, where the 400 MHz bandwidth may be set based on a 400 MHzper carrier bandwidth limit.

FIG. 8 illustrates a single numerology being used across the entirebandwidth of the NR carrier. In other example configurations, multiplenumerologies may be supported on the same carrier.

NR may support wide carrier bandwidths (e.g., up to 400 MHz for asubcarrier spacing of 120 kHz). Not all UEs may be able to receive thefull carrier bandwidth (e.g., due to hardware limitations). Also,receiving the full carrier bandwidth may be prohibitive in terms of UEpower consumption. In an example, to reduce power consumption and/or forother purposes, a UE may adapt the size of the UE's receive bandwidthbased on the amount of traffic the UE is scheduled to receive. This isreferred to as bandwidth adaptation.

NR defines bandwidth parts (BWPs) to support UEs not capable ofreceiving the full carrier bandwidth and to support bandwidthadaptation. In an example, a BWP may be defined by a subset ofcontiguous RBs on a carrier. A UE may be configured (e.g., via RRClayer) with one or more downlink BWPs and one or more uplink BWPs perserving cell (e.g., up to four downlink BWPs and up to four uplink BWPsper serving cell). At a given time, one or more of the configured BWPsfor a serving cell may be active. These one or more BWPs may be referredto as active BWPs of the serving cell. When a serving cell is configuredwith a secondary uplink carrier, the serving cell may have one or morefirst active BWPs in the uplink carrier and one or more second activeBWPs in the secondary uplink carrier.

For unpaired spectra, a downlink BWP from a set of configured downlinkBWPs may be linked with an uplink BWP from a set of configured uplinkBWPs if a downlink BWP index of the downlink BWP and an uplink BWP indexof the uplink BWP are the same. For unpaired spectra, a UE may expectthat a center frequency for a downlink BWP is the same as a centerfrequency for an uplink BWP.

For a downlink BWP in a set of configured downlink BWPs on a primarycell (PCell), a base station may configure a UE with one or more controlresource sets (CORESETs) for at least one search space. A search spaceis a set of locations in the time and frequency domains where the UE mayfind control information. The search space may be a UE-specific searchspace or a common search space (potentially usable by a plurality ofUEs). For example, a base station may configure a UE with a commonsearch space, on a PCell or on a primary secondary cell (PSCell), in anactive downlink BWP.

For an uplink BWP in a set of configured uplink BWPs, a BS may configurea UE with one or more resource sets for one or more PUCCH transmissions.A UE may receive downlink receptions (e.g., PDCCH or PDSCH) in adownlink BWP according to a configured numerology (e.g., subcarrierspacing and cyclic prefix duration) for the downlink BWP. The UE maytransmit uplink transmissions (e.g., PUCCH or PUSCH) in an uplink BWPaccording to a configured numerology (e.g., subcarrier spacing andcyclic prefix length for the uplink BWP).

One or more BWP indicator fields may be provided in Downlink ControlInformation (DCI). A value of a BWP indicator field may indicate whichBWP in a set of configured BWPs is an active downlink BWP for one ormore downlink receptions. The value of the one or more BWP indicatorfields may indicate an active uplink BWP for one or more uplinktransmissions.

A base station may semi-statically configure a UE with a defaultdownlink BWP within a set of configured downlink BWPs associated with aPCell. If the base station does not provide the default downlink BWP tothe UE, the default downlink BWP may be an initial active downlink BWP.The UE may determine which BWP is the initial active downlink BWP basedon a CORESET configuration obtained using the PBCH.

A base station may configure a UE with a BWP inactivity timer value fora PCell. The UE may start or restart a BWP inactivity timer at anyappropriate time. For example, the UE may start or restart the BWPinactivity timer (a) when the UE detects a DCI indicating an activedownlink BWP other than a default downlink BWP for a paired spectraoperation; or (b) when a UE detects a DCI indicating an active downlinkBWP or active uplink BWP other than a default downlink BWP or uplink BWPfor an unpaired spectra operation. If the UE does not detect DCI duringan interval of time (e.g., 1 ms or 0.5 ms), the UE may run the BWPinactivity timer toward expiration (for example, increment from zero tothe BWP inactivity timer value, or decrement from the BWP inactivitytimer value to zero). When the BWP inactivity timer expires, the UE mayswitch from the active downlink BWP to the default downlink BWP.

In an example, a base station may semi-statically configure a UE withone or more BWPs. A UE may switch an active BWP from a first BWP to asecond BWP in response to receiving a DCI indicating the second BWP asan active BWP and/or in response to an expiry of the BWP inactivitytimer (e.g., if the second BWP is the default BWP).

Downlink and uplink BWP switching (where BWP switching refers toswitching from a currently active BWP to a not currently active BWP) maybe performed independently in paired spectra. In unpaired spectra,downlink and uplink BWP switching may be performed simultaneously.Switching between configured BWPs may occur based on RRC signaling, DCI,expiration of a BWP inactivity timer, and/or an initiation of randomaccess.

FIG. 9 illustrates an example of bandwidth adaptation using threeconfigured BWPs for an NR carrier. A UE configured with the three BWPsmay switch from one BWP to another BWP at a switching point. In theexample illustrated in FIG. 9 , the BWPs include: a BWP 902 with abandwidth of 40 MHz and a subcarrier spacing of 15 kHz; a BWP 904 with abandwidth of 10 MHz and a subcarrier spacing of 15 kHz; and a BWP 906with a bandwidth of 20 MHz and a subcarrier spacing of 60 kHz. The BWP902 may be an initial active BWP, and the BWP 904 may be a default BWP.The UE may switch between BWPs at switching points. In the example ofFIG. 9 , the UE may switch from the BWP 902 to the BWP 904 at aswitching point 908. The switching at the switching point 908 may occurfor any suitable reason, for example, in response to an expiry of a BWPinactivity timer (indicating switching to the default BWP) and/or inresponse to receiving a DCI indicating BWP 904 as the active BWP. The UEmay switch at a switching point 910 from active BWP 904 to BWP 906 inresponse receiving a DCI indicating BWP 906 as the active BWP. The UEmay switch at a switching point 912 from active BWP 906 to BWP 904 inresponse to an expiry of a BWP inactivity timer and/or in responsereceiving a DCI indicating BWP 904 as the active BWP. The UE may switchat a switching point 914 from active BWP 904 to BWP 902 in responsereceiving a DCI indicating BWP 902 as the active BWP.

If a UE is configured for a secondary cell with a default downlink BWPin a set of configured downlink BWPs and a timer value, UE proceduresfor switching BWPs on a secondary cell may be the same/similar as thoseon a primary cell. For example, the UE may use the timer value and thedefault downlink BWP for the secondary cell in the same/similar manneras the UE would use these values for a primary cell.

To provide for greater data rates, two or more carriers can beaggregated and simultaneously transmitted to/from the same UE usingcarrier aggregation (CA). The aggregated carriers in CA may be referredto as component carriers (CCs). When CA is used, there are a number ofserving cells for the UE, one for a CC. The CCs may have threeconfigurations in the frequency domain.

FIG. 10A illustrates the three CA configurations with two CCs. In theintraband, contiguous configuration 1002, the two CCs are aggregated inthe same frequency band (frequency band A) and are located directlyadjacent to each other within the frequency band. In the intraband,non-contiguous configuration 1004, the two CCs are aggregated in thesame frequency band (frequency band A) and are separated in thefrequency band by a gap. In the interband configuration 1006, the twoCCs are located in frequency bands (frequency band A and frequency bandB).

In an example, up to 32 CCs may be aggregated. The aggregated CCs mayhave the same or different bandwidths, subcarrier spacing, and/orduplexing schemes (TDD or FDD). A serving cell for a UE using CA mayhave a downlink CC. For FDD, one or more uplink CCs may be optionallyconfigured for a serving cell. The ability to aggregate more downlinkcarriers than uplink carriers may be useful, for example, when the UEhas more data traffic in the downlink than in the uplink.

When CA is used, one of the aggregated cells for a UE may be referred toas a primary cell (PCell). The PCell may be the serving cell that the UEinitially connects to at RRC connection establishment, reestablishment,and/or handover. The PCell may provide the UE with NAS mobilityinformation and the security input. UEs may have different PCells. Inthe downlink, the carrier corresponding to the PCell may be referred toas the downlink primary CC (DL PCC). In the uplink, the carriercorresponding to the PCell may be referred to as the uplink primary CC(UL PCC). The other aggregated cells for the UE may be referred to assecondary cells (SCells). In an example, the SCells may be configuredafter the PCell is configured for the UE. For example, an SCell may beconfigured through an RRC Connection Reconfiguration procedure. In thedownlink, the carrier corresponding to an SCell may be referred to as adownlink secondary CC (DL SCC). In the uplink, the carrier correspondingto the SCell may be referred to as the uplink secondary CC (UL SCC).

Configured SCells for a UE may be activated and deactivated based on,for example, traffic and channel conditions. Deactivation of an SCellmay mean that PDCCH and PDSCH reception on the SCell is stopped andPUSCH, SRS, and CQI transmissions on the SCell are stopped. ConfiguredSCells may be activated and deactivated using a MAC CE with respect toFIG. 4B. For example, a MAC CE may use a bitmap (e.g., one bit perSCell) to indicate which SCells (e.g., in a subset of configured SCells)for the UE are activated or deactivated. Configured SCells may bedeactivated in response to an expiration of an SCell deactivation timer(e.g., one SCell deactivation timer per SCell).

Downlink control information, such as scheduling assignments andscheduling grants, for a cell may be transmitted on the cellcorresponding to the assignments and grants, which is known asself-scheduling. The DCI for the cell may be transmitted on anothercell, which is known as cross-carrier scheduling. Uplink controlinformation (e.g., HARQ acknowledgments and channel state feedback, suchas CQI, PMI, and/or RI) for aggregated cells may be transmitted on thePUCCH of the PCell. For a larger number of aggregated downlink CCs, thePUCCH of the PCell may become overloaded. Cells may be divided intomultiple PUCCH groups.

FIG. 10B illustrates an example of how aggregated cells may beconfigured into one or more PUCCH groups. A PUCCH group 1010 and a PUCCHgroup 1050 may include one or more downlink CCs, respectively. In theexample of FIG. 10B, the PUCCH group 1010 includes three downlink CCs: aPCell 1011, an SCell 1012, and an SCell 1013. The PUCCH group 1050includes three downlink CCs in the present example: a PCell 1051, anSCell 1052, and an SCell 1053. One or more uplink CCs may be configuredas a PCell 1021, an SCell 1022, and an SCell 1023. One or more otheruplink CCs may be configured as a primary Scell (PSCell) 1061, an SCell1062, and an SCell 1063. Uplink control information (UCI) related to thedownlink CCs of the PUCCH group 1010, shown as UCI 1031, UCI 1032, andUCI 1033, may be transmitted in the uplink of the PCell 1021. Uplinkcontrol information (UCI) related to the downlink CCs of the PUCCH group1050, shown as UCI 1071, UCI 1072, and UCI 1073, may be transmitted inthe uplink of the PSCell 1061. In an example, if the aggregated cellsdepicted in FIG. 10B were not divided into the PUCCH group 1010 and thePUCCH group 1050, a single uplink PCell to transmit UCI relating to thedownlink CCs, and the PCell may become overloaded. By dividingtransmissions of UCI between the PCell 1021 and the PSCell 1061,overloading may be prevented.

A cell, comprising a downlink carrier and optionally an uplink carrier,may be assigned with a physical cell ID and a cell index. The physicalcell ID or the cell index may identify a downlink carrier and/or anuplink carrier of the cell, for example, depending on the context inwhich the physical cell ID is used. A physical cell ID may be determinedusing a synchronization signal transmitted on a downlink componentcarrier. A cell index may be determined using RRC messages. In thedisclosure, a physical cell ID may be referred to as a carrier ID, and acell index may be referred to as a carrier index. For example, when thedisclosure refers to a first physical cell ID for a first downlinkcarrier, the disclosure may mean the first physical cell ID is for acell comprising the first downlink carrier. The same/similar concept mayapply to, for example, a carrier activation. When the disclosureindicates that a first carrier is activated, the specification may meanthat a cell comprising the first carrier is activated.

In CA, a multi-carrier nature of a PHY may be exposed to a MAC. In anexample, a HARQ entity may operate on a serving cell. A transport blockmay be generated per assignment/grant per serving cell. A transportblock and potential HARQ retransmissions of the transport block may bemapped to a serving cell.

In the downlink, a base station may transmit (e.g., unicast, multicast,and/or broadcast) one or more Reference Signals (RSs) to a UE (e.g.,PSS, SSS, CSI-RS, DMRS, and/or PT-RS, as shown in FIG. 5A). In theuplink, the UE may transmit one or more RSs to the base station (e.g.,DMRS, PT-RS, and/or SRS, as shown in FIG. 5B). The PSS and the SSS maybe transmitted by the base station and used by the UE to synchronize theUE to the base station. The PSS and the SSS may be provided in asynchronization signal (SS)/physical broadcast channel (PBCH) block thatincludes the PSS, the SSS, and the PBCH. The base station mayperiodically transmit a burst of SS/PBCH blocks.

FIG. 11A illustrates an example of an SS/PBCH block's structure andlocation. A burst of SS/PBCH blocks may include one or more SS/PBCHblocks (e.g., 4 SS/PBCH blocks, as shown in FIG. 11A). Bursts may betransmitted periodically (e.g., every 2 frames or 20 ms). A burst may berestricted to a half-frame (e.g., a first half-frame having a durationof 5 ms). It will be understood that FIG. 11A is an example, and thatthese parameters (number of SS/PBCH blocks per burst, periodicity ofbursts, position of burst within the frame) may be configured based on,for example: a carrier frequency of a cell in which the SS/PBCH block istransmitted; a numerology or subcarrier spacing of the cell; aconfiguration by the network (e.g., using RRC signaling); or any othersuitable factor. In an example, the UE may assume a subcarrier spacingfor the SS/PBCH block based on the carrier frequency being monitored,unless the radio network configured the UE to assume a differentsubcarrier spacing.

The SS/PBCH block may span one or more OFDM symbols in the time domain(e.g., 4 OFDM symbols, as shown in the example of FIG. 11A) and may spanone or more subcarriers in the frequency domain (e.g., 240 contiguoussubcarriers). The PSS, the SSS, and the PBCH may have a common centerfrequency. The PSS may be transmitted first and may span, for example, 1OFDM symbol and 127 subcarriers. The SSS may be transmitted after thePSS (e.g., two symbols later) and may span 1 OFDM symbol and 127subcarriers. The PBCH may be transmitted after the PSS (e.g., across thenext 3 OFDM symbols) and may span 240 subcarriers.

The location of the SS/PBCH block in the time and frequency domains maynot be known to the UE (e.g., if the UE is searching for the cell). Tofind and select the cell, the UE may monitor a carrier for the PSS. Forexample, the UE may monitor a frequency location within the carrier. Ifthe PSS is not found after a certain duration (e.g., 20 ms), the UE maysearch for the PSS at a different frequency location within the carrier,as indicated by a synchronization raster. If the PSS is found at alocation in the time and frequency domains, the UE may determine, basedon a known structure of the SS/PBCH block, the locations of the SSS andthe PBCH, respectively. The SS/PBCH block may be a cell-defining SSblock (CD-SSB). In an example, a primary cell may be associated with aCD-SSB. The CD-SSB may be located on a synchronization raster. In anexample, a cell selection/search and/or reselection may be based on theCD-SSB.

The SS/PBCH block may be used by the UE to determine one or moreparameters of the cell. For example, the UE may determine a physicalcell identifier (PCI) of the cell based on the sequences of the PSS andthe SSS, respectively. The UE may determine a location of a frameboundary of the cell based on the location of the SS/PBCH block. Forexample, the SS/PBCH block may indicate that it has been transmitted inaccordance with a transmission pattern, wherein a SS/PBCH block in thetransmission pattern is a known distance from the frame boundary.

The PBCH may use a QPSK modulation and may use forward error correction(FEC). The FEC may use polar coding. One or more symbols spanned by thePBCH may carry one or more DMRSs for demodulation of the PBCH. The PBCHmay include an indication of a current system frame number (SFN) of thecell and/or a SS/PBCH block timing index. These parameters mayfacilitate time synchronization of the UE to the base station. The PBCHmay include a master information block (MIB) used to provide the UE withone or more parameters. The MIB may be used by the UE to locateremaining minimum system information (RMSI) associated with the cell.The RMSI may include a System Information Block Type 1 (SIB1). The SIB1may contain information needed by the UE to access the cell. The UE mayuse one or more parameters of the MIB to monitor PDCCH, which may beused to schedule PDSCH. The PDSCH may include the SIB1. The SIB1 may bedecoded using parameters provided in the MIB. The PBCH may indicate anabsence of SIB1. Based on the PBCH indicating the absence of SIB1, theUE may be pointed to a frequency. The UE may search for an SS/PBCH blockat the frequency to which the UE is pointed.

The UE may assume that one or more SS/PBCH blocks transmitted with asame SS/PBCH block index are quasi co-located (QCLed) (e.g., having thesame/similar Doppler spread, Doppler shift, average gain, average delay,and/or spatial Rx parameters). The UE may not assume QCL for SS/PBCHblock transmissions having different SS/PBCH block indices.

SS/PBCH blocks (e.g., those within a half-frame) may be transmitted inspatial directions (e.g., using different beams that span a coveragearea of the cell). In an example, a first SS/PBCH block may betransmitted in a first spatial direction using a first beam, and asecond SS/PBCH block may be transmitted in a second spatial directionusing a second beam.

In an example, within a frequency span of a carrier, a base station maytransmit a plurality of SS/PBCH blocks. In an example, a first PCI of afirst SS/PBCH block of the plurality of SS/PBCH blocks may be differentfrom a second PCI of a second SS/PBCH block of the plurality of SS/PBCHblocks. The PCIs of SS/PBCH blocks transmitted in different frequencylocations may be different or the same.

The CSI-RS may be transmitted by the base station and used by the UE toacquire channel state information (CSI). The base station may configurethe UE with one or more CSI-RSs for channel estimation or any othersuitable purpose. The base station may configure a UE with one or moreof the same/similar CSI-RSs. The UE may measure the one or more CSI-RSs.The UE may estimate a downlink channel state and/or generate a CSIreport based on the measuring of the one or more downlink CSI-RSs. TheUE may provide the CSI report to the base station. The base station mayuse feedback provided by the UE (e.g., the estimated downlink channelstate) to perform link adaptation.

The base station may semi-statically configure the UE with one or moreCSI-RS resource sets. A CSI-RS resource may be associated with alocation in the time and frequency domains and a periodicity. The basestation may selectively activate and/or deactivate a CSI-RS resource.The base station may indicate to the UE that a CSI-RS resource in theCSI-RS resource set is activated and/or deactivated.

The base station may configure the UE to report CSI measurements. Thebase station may configure the UE to provide CSI reports periodically,aperiodically, or semi-persistently. For periodic CSI reporting, the UEmay be configured with a timing and/or periodicity of a plurality of CSIreports. For aperiodic CSI reporting, the base station may request a CSIreport. For example, the base station may command the UE to measure aconfigured CSI-RS resource and provide a CSI report relating to themeasurements. For semi-persistent CSI reporting, the base station mayconfigure the UE to transmit periodically, and selectively activate ordeactivate the periodic reporting. The base station may configure the UEwith a CSI-RS resource set and CSI reports using RRC signaling.

The CSI-RS configuration may comprise one or more parameters indicating,for example, up to 32 antenna ports. The UE may be configured to employthe same OFDM symbols for a downlink CSI-RS and a control resource set(CORESET) when the downlink CSI-RS and CORESET are spatially QCLed andresource elements associated with the downlink CSI-RS are outside of thephysical resource blocks (PRBs) configured for the CORESET. The UE maybe configured to employ the same OFDM symbols for downlink CSI-RS andSS/PBCH blocks when the downlink CSI-RS and SS/PBCH blocks are spatiallyQCLed and resource elements associated with the downlink CSI-RS areoutside of PRBs configured for the SS/PBCH blocks.

Downlink DMRSs may be transmitted by a base station and used by a UE forchannel estimation. For example, the downlink DMRS may be used forcoherent demodulation of one or more downlink physical channels (e.g.,PDSCH). An NR network may support one or more variable and/orconfigurable DMRS patterns for data demodulation. At least one downlinkDMRS configuration may support a front-loaded DMRS pattern. Afront-loaded DMRS may be mapped over one or more OFDM symbols (e.g., oneor two adjacent OFDM symbols). A base station may semi-staticallyconfigure the UE with a number (e.g. a maximum number) of front-loadedDMRS symbols for PDSCH. A DMRS configuration may support one or moreDMRS ports. For example, for single user-MIMO, a DMRS configuration maysupport up to eight orthogonal downlink DMRS ports per UE. Formultiuser-MIMO, a DMRS configuration may support up to 4 orthogonaldownlink DMRS ports per UE. A radio network may support (e.g., at leastfor CP-OFDM) a common DMRS structure for downlink and uplink, wherein aDMRS location, a DMRS pattern, and/or a scrambling sequence may be thesame or different. The base station may transmit a downlink DMRS and acorresponding PDSCH using the same precoding matrix. The UE may use theone or more downlink DMRSs for coherent demodulation/channel estimationof the PDSCH.

In an example, a transmitter (e.g., a base station) may use a precodermatrices for a part of a transmission bandwidth. For example, thetransmitter may use a first precoder matrix for a first bandwidth and asecond precoder matrix for a second bandwidth. The first precoder matrixand the second precoder matrix may be different based on the firstbandwidth being different from the second bandwidth. The UE may assumethat a same precoding matrix is used across a set of PRBs. The set ofPRBs may be denoted as a precoding resource block group (PRG).

A PDSCH may comprise one or more layers. The UE may assume that at leastone symbol with DMRS is present on a layer of the one or more layers ofthe PDSCH. A higher layer may configure up to 3 DMRSs for the PDSCH.

Downlink PT-RS may be transmitted by a base station and used by a UE forphase-noise compensation. Whether a downlink PT-RS is present or not maydepend on an RRC configuration. The presence and/or pattern of thedownlink PT-RS may be configured on a UE-specific basis using acombination of RRC signaling and/or an association with one or moreparameters employed for other purposes (e.g., modulation and codingscheme (MCS)), which may be indicated by DCI. When configured, a dynamicpresence of a downlink PT-RS may be associated with one or more DCIparameters comprising at least MCS. An NR network may support aplurality of PT-RS densities defined in the time and/or frequencydomains. When present, a frequency domain density may be associated withat least one configuration of a scheduled bandwidth. The UE may assume asame precoding for a DMRS port and a PT-RS port. A number of PT-RS portsmay be fewer than a number of DMRS ports in a scheduled resource.Downlink PT-RS may be confined in the scheduled time/frequency durationfor the UE. Downlink PT-RS may be transmitted on symbols to facilitatephase tracking at the receiver.

The UE may transmit an uplink DMRS to a base station for channelestimation. For example, the base station may use the uplink DMRS forcoherent demodulation of one or more uplink physical channels. Forexample, the UE may transmit an uplink DMRS with a PUSCH and/or a PUCCH.The uplink DM-RS may span a range of frequencies that is similar to arange of frequencies associated with the corresponding physical channel.The base station may configure the UE with one or more uplink DMRSconfigurations. At least one DMRS configuration may support afront-loaded DMRS pattern. The front-loaded DMRS may be mapped over oneor more OFDM symbols (e.g., one or two adjacent OFDM symbols). One ormore uplink DMRSs may be configured to transmit at one or more symbolsof a PUSCH and/or a PUCCH. The base station may semi-staticallyconfigure the UE with a number (e.g. maximum number) of front-loadedDMRS symbols for the PUSCH and/or the PUCCH, which the UE may use toschedule a single-symbol DMRS and/or a double-symbol DMRS. An NR networkmay support (e.g., for cyclic prefix orthogonal frequency divisionmultiplexing (CP-OFDM)) a common DMRS structure for downlink and uplink,wherein a DMRS location, a DMRS pattern, and/or a scrambling sequencefor the DMRS may be the same or different.

A PUSCH may comprise one or more layers, and the UE may transmit atleast one symbol with DMRS present on a layer of the one or more layersof the PUSCH. In an example, a higher layer may configure up to threeDMRSs for the PUSCH.

Uplink PT-RS (which may be used by a base station for phase trackingand/or phase-noise compensation) may or may not be present depending onan RRC configuration of the UE. The presence and/or pattern of uplinkPT-RS may be configured on a UE-specific basis by a combination of RRCsignaling and/or one or more parameters employed for other purposes(e.g., Modulation and Coding Scheme (MCS)), which may be indicated byDCI. When configured, a dynamic presence of uplink PT-RS may beassociated with one or more DCI parameters comprising at least MCS. Aradio network may support a plurality of uplink PT-RS densities definedin time/frequency domain. When present, a frequency domain density maybe associated with at least one configuration of a scheduled bandwidth.The UE may assume a same precoding for a DMRS port and a PT-RS port. Anumber of PT-RS ports may be fewer than a number of DMRS ports in ascheduled resource. For example, uplink PT-RS may be confined in thescheduled time/frequency duration for the UE.

SRS may be transmitted by a UE to a base station for channel stateestimation to support uplink channel dependent scheduling and/or linkadaptation. SRS transmitted by the UE may allow a base station toestimate an uplink channel state at one or more frequencies. A schedulerat the base station may employ the estimated uplink channel state toassign one or more resource blocks for an uplink PUSCH transmission fromthe UE. The base station may semi-statically configure the UE with oneor more SRS resource sets. For an SRS resource set, the base station mayconfigure the UE with one or more SRS resources. An SRS resource setapplicability may be configured by a higher layer (e.g., RRC) parameter.For example, when a higher layer parameter indicates beam management, anSRS resource in a SRS resource set of the one or more SRS resource sets(e.g., with the same/similar time domain behavior, periodic, aperiodic,and/or the like) may be transmitted at a time instant (e.g.,simultaneously). The UE may transmit one or more SRS resources in SRSresource sets. An NR network may support aperiodic, periodic and/orsemi-persistent SRS transmissions. The UE may transmit SRS resourcesbased on one or more trigger types, wherein the one or more triggertypes may comprise higher layer signaling (e.g., RRC) and/or one or moreDCI formats. In an example, at least one DCI format may be employed forthe UE to select at least one of one or more configured SRS resourcesets. An SRS trigger type 0 may refer to an SRS triggered based on ahigher layer signaling. An SRS trigger type 1 may refer to an SRStriggered based on one or more DCI formats. In an example, when PUSCHand SRS are transmitted in a same slot, the UE may be configured totransmit SRS after a transmission of a PUSCH and a corresponding uplinkDMRS.

The base station may semi-statically configure the UE with one or moreSRS configuration parameters indicating at least one of following: a SRSresource configuration identifier; a number of SRS ports; time domainbehavior of an SRS resource configuration (e.g., an indication ofperiodic, semi-persistent, or aperiodic SRS); slot, mini-slot, and/orsubframe level periodicity; offset for a periodic and/or an aperiodicSRS resource; a number of OFDM symbols in an SRS resource; a startingOFDM symbol of an SRS resource; an SRS bandwidth; a frequency hoppingbandwidth; a cyclic shift; and/or an SRS sequence ID.

An antenna port is defined such that the channel over which a symbol onthe antenna port is conveyed can be inferred from the channel over whichanother symbol on the same antenna port is conveyed. If a first symboland a second symbol are transmitted on the same antenna port, thereceiver may infer the channel (e.g., fading gain, multipath delay,and/or the like) for conveying the second symbol on the antenna port,from the channel for conveying the first symbol on the antenna port. Afirst antenna port and a second antenna port may be referred to as quasico-located (QCLed) if one or more large-scale properties of the channelover which a first symbol on the first antenna port is conveyed may beinferred from the channel over which a second symbol on a second antennaport is conveyed. The one or more large-scale properties may comprise atleast one of: a delay spread; a Doppler spread; a Doppler shift; anaverage gain; an average delay; and/or spatial Receiving (Rx)parameters.

Channels that use beamforming require beam management. Beam managementmay comprise beam measurement, beam selection, and beam indication. Abeam may be associated with one or more reference signals. For example,a beam may be identified by one or more beamformed reference signals.The UE may perform downlink beam measurement based on downlink referencesignals (e.g., a channel state information reference signal (CSI-RS))and generate a beam measurement report. The UE may perform the downlinkbeam measurement procedure after an RRC connection is set up with a basestation.

FIG. 11B illustrates an example of channel state information referencesignals (CSI-RS s) that are mapped in the time and frequency domains. Asquare shown in FIG. 11B may span a resource block (RB) within abandwidth of a cell. A base station may transmit one or more RRCmessages comprising CSI-RS resource configuration parameters indicatingone or more CSI-RSs. One or more of the following parameters may beconfigured by higher layer signaling (e.g., RRC and/or MAC signaling)for a CSI-RS resource configuration: a CSI-RS resource configurationidentity, a number of CSI-RS ports, a CSI-RS configuration (e.g., symboland resource element (RE) locations in a subframe), a CSI-RS subframeconfiguration (e.g., subframe location, offset, and periodicity in aradio frame), a CSI-RS power parameter, a CSI-RS sequence parameter, acode division multiplexing (CDM) type parameter, a frequency density, atransmission comb, quasi co-location (QCL) parameters (e.g.,QCL-scramblingidentity, crs-portscount, mbsfn-subframeconfiglist,csi-rs-configZPid, qcl-csi-rs-configNZPid), and/or other radio resourceparameters.

The three beams illustrated in FIG. 11B may be configured for a UE in aUE-specific configuration. Three beams are illustrated in FIG. 11B (beam#1, beam #2, and beam #3), more or fewer beams may be configured. Beam#1 may be allocated with CSI-RS 1101 that may be transmitted in one ormore subcarriers in an RB of a first symbol. Beam #2 may be allocatedwith CSI-RS 1102 that may be transmitted in one or more subcarriers inan RB of a second symbol. Beam #3 may be allocated with CSI-RS 1103 thatmay be transmitted in one or more subcarriers in an RB of a thirdsymbol. By using frequency division multiplexing (FDM), a base stationmay use other subcarriers in a same RB (for example, those that are notused to transmit CSI-RS 1101) to transmit another CSI-RS associated witha beam for another UE. By using time domain multiplexing (TDM), beamsused for the UE may be configured such that beams for the UE use symbolsfrom beams of other UEs.

CSI-RSs such as those illustrated in FIG. 11B (e.g., CSI-RS 1101, 1102,1103) may be transmitted by the base station and used by the UE for oneor more measurements. For example, the UE may measure a reference signalreceived power (RSRP) of configured CSI-RS resources. The base stationmay configure the UE with a reporting configuration and the UE mayreport the RSRP measurements to a network (for example, via one or morebase stations) based on the reporting configuration. In an example, thebase station may determine, based on the reported measurement results,one or more transmission configuration indication (TCI) statescomprising a number of reference signals. In an example, the basestation may indicate one or more TCI states to the UE (e.g., via RRCsignaling, a MAC CE, and/or a DCI). The UE may receive a downlinktransmission with a receive (Rx) beam determined based on the one ormore TCI states. In an example, the UE may or may not have a capabilityof beam correspondence. If the UE has the capability of beamcorrespondence, the UE may determine a spatial domain filter of atransmit (Tx) beam based on a spatial domain filter of the correspondingRx beam. If the UE does not have the capability of beam correspondence,the UE may perform an uplink beam selection procedure to determine thespatial domain filter of the Tx beam. The UE may perform the uplink beamselection procedure based on one or more sounding reference signal (SRS)resources configured to the UE by the base station. The base station mayselect and indicate uplink beams for the UE based on measurements of theone or more SRS resources transmitted by the UE.

In a beam management procedure, a UE may assess (e.g., measure) achannel quality of one or more beam pair links, a beam pair linkcomprising a transmitting beam transmitted by a base station and areceiving beam received by the UE. Based on the assessment, the UE maytransmit a beam measurement report indicating one or more beam pairquality parameters comprising, e.g., one or more beam identifications(e.g., a beam index, a reference signal index, or the like), RSRP, aprecoding matrix indicator (PMI), a channel quality indicator (CQI),and/or a rank indicator (RI).

FIG. 12A illustrates examples of three downlink beam managementprocedures: P1, P2, and P3. Procedure P1 may enable a UE measurement ontransmit (Tx) beams of a transmission reception point (TRP) (or multipleTRPs), e.g., to support a selection of one or more base station Tx beamsand/or UE Rx beams (shown as ovals in the top row and bottom row,respectively, of P1). Beamforming at a TRP may comprise a Tx beam sweepfor a set of beams (shown, in the top rows of P1 and P2, as ovalsrotated in a counter-clockwise direction indicated by the dashed arrow).Beamforming at a UE may comprise an Rx beam sweep for a set of beams(shown, in the bottom rows of P1 and P3, as ovals rotated in a clockwisedirection indicated by the dashed arrow). Procedure P2 may be used toenable a UE measurement on Tx beams of a TRP (shown, in the top row ofP2, as ovals rotated in a counter-clockwise direction indicated by thedashed arrow). The UE and/or the base station may perform procedure P2using a smaller set of beams than is used in procedure P1, or usingnarrower beams than the beams used in procedure P1. This may be referredto as beam refinement. The UE may perform procedure P3 for Rx beamdetermination by using the same Tx beam at the base station and sweepingan Rx beam at the UE.

FIG. 12B illustrates examples of three uplink beam managementprocedures: U1, U2, and U3. Procedure U1 may be used to enable a basestation to perform a measurement on Tx beams of a UE, e.g., to support aselection of one or more UE Tx beams and/or base station Rx beams (shownas ovals in the top row and bottom row, respectively, of U1).Beamforming at the UE may include, e.g., a Tx beam sweep from a set ofbeams (shown in the bottom rows of U1 and U3 as ovals rotated in aclockwise direction indicated by the dashed arrow). Beamforming at thebase station may include, e.g., an Rx beam sweep from a set of beams(shown, in the top rows of U1 and U2, as ovals rotated in acounter-clockwise direction indicated by the dashed arrow). Procedure U2may be used to enable the base station to adjust its Rx beam when the UEuses a fixed Tx beam. The UE and/or the base station may performprocedure U2 using a smaller set of beams than is used in procedure P1,or using narrower beams than the beams used in procedure P1. This may bereferred to as beam refinement The UE may perform procedure U3 to adjustits Tx beam when the base station uses a fixed Rx beam.

A UE may initiate a beam failure recovery (BFR) procedure based ondetecting a beam failure. The UE may transmit a BFR request (e.g., apreamble, a UCI, an SR, a MAC CE, and/or the like) based on theinitiating of the BFR procedure. The UE may detect the beam failurebased on a determination that a quality of beam pair link(s) of anassociated control channel is unsatisfactory (e.g., having an error ratehigher than an error rate threshold, a received signal power lower thana received signal power threshold, an expiration of a timer, and/or thelike).

The UE may measure a quality of a beam pair link using one or morereference signals (RSs) comprising one or more SS/PBCH blocks, one ormore CSI-RS resources, and/or one or more demodulation reference signals(DMRSs). A quality of the beam pair link may be based on one or more ofa block error rate (BLER), an RSRP value, a signal to interference plusnoise ratio (SINR) value, a reference signal received quality (RSRQ)value, and/or a CSI value measured on RS resources. The base station mayindicate that an RS resource is quasi co-located (QCLed) with one ormore DM-RSs of a channel (e.g., a control channel, a shared datachannel, and/or the like). The RS resource and the one or more DMRSs ofthe channel may be QCLed when the channel characteristics (e.g., Dopplershift, Doppler spread, average delay, delay spread, spatial Rxparameter, fading, and/or the like) from a transmission via the RSresource to the UE are similar or the same as the channelcharacteristics from a transmission via the channel to the UE.

A network (e.g., a gNB and/or an ng-eNB of a network) and/or the UE mayinitiate a random access procedure. A UE in an RRC_IDLE state and/or anRRC_INACTIVE state may initiate the random access procedure to request aconnection setup to a network. The UE may initiate the random accessprocedure from an RRC_CONNECTED state. The UE may initiate the randomaccess procedure to request uplink resources (e.g., for uplinktransmission of an SR when there is no PUCCH resource available) and/oracquire uplink timing (e.g., when uplink synchronization status isnon-synchronized). The UE may initiate the random access procedure torequest one or more system information blocks (SIBs) (e.g., other systeminformation such as SIB2, SIB3, and/or the like). The UE may initiatethe random access procedure for a beam failure recovery request. Anetwork may initiate a random access procedure for a handover and/or forestablishing time alignment for an SCell addition.

FIG. 13A illustrates a four-step contention-based random accessprocedure. Prior to initiation of the procedure, a base station maytransmit a configuration message 1310 to the UE. The procedureillustrated in FIG. 13A comprises transmission of four messages: a Msg 11311, a Msg 2 1312, a Msg 3 1313, and a Msg 4 1314. The Msg 1 1311 mayinclude and/or be referred to as a preamble (or a random accesspreamble). The Msg 2 1312 may include and/or be referred to as a randomaccess response (RAR).

The configuration message 1310 may be transmitted, for example, usingone or more RRC messages. The one or more RRC messages may indicate oneor more random access channel (RACH) parameters to the UE. The one ormore RACH parameters may comprise at least one of following: generalparameters for one or more random access procedures (e.g.,RACH-configGeneral); cell-specific parameters (e.g., RACH-ConfigCommon);and/or dedicated parameters (e.g., RACH-configDedicated). The basestation may broadcast or multicast the one or more RRC messages to oneor more UEs. The one or more RRC messages may be UE-specific (e.g.,dedicated RRC messages transmitted to a UE in an RRC_CONNECTED stateand/or in an RRC_INACTIVE state). The UE may determine, based on the oneor more RACH parameters, a time-frequency resource and/or an uplinktransmit power for transmission of the Msg 1 1311 and/or the Msg 3 1313.Based on the one or more RACH parameters, the UE may determine areception timing and a downlink channel for receiving the Msg 2 1312 andthe Msg 4 1314.

The one or more RACH parameters provided in the configuration message1310 may indicate one or more Physical RACH (PRACH) occasions availablefor transmission of the Msg 1 1311. The one or more PRACH occasions maybe predefined. The one or more RACH parameters may indicate one or moreavailable sets of one or more PRACH occasions (e.g., prach-ConfigIndex).The one or more RACH parameters may indicate an association between (a)one or more PRACH occasions and (b) one or more reference signals. Theone or more RACH parameters may indicate an association between (a) oneor more preambles and (b) one or more reference signals. The one or morereference signals may be SS/PBCH blocks and/or CSI-RSs. For example, theone or more RACH parameters may indicate a number of SS/PBCH blocksmapped to a PRACH occasion and/or a number of preambles mapped to aSS/PBCH blocks.

The one or more RACH parameters provided in the configuration message1310 may be used to determine an uplink transmit power of Msg 1 1311and/or Msg 3 1313. For example, the one or more RACH parameters mayindicate a reference power for a preamble transmission (e.g., a receivedtarget power and/or an initial power of the preamble transmission).There may be one or more power offsets indicated by the one or more RACHparameters. For example, the one or more RACH parameters may indicate: apower ramping step; a power offset between SSB and CSI-RS; a poweroffset between transmissions of the Msg 1 1311 and the Msg 3 1313;and/or a power offset value between preamble groups. The one or moreRACH parameters may indicate one or more thresholds based on which theUE may determine at least one reference signal (e.g., an SSB and/orCSI-RS) and/or an uplink carrier (e.g., a normal uplink (NUL) carrierand/or a supplemental uplink (SUL) carrier).

The Msg 1 1311 may include one or more preamble transmissions (e.g., apreamble transmission and one or more preamble retransmissions). An RRCmessage may be used to configure one or more preamble groups (e.g.,group A and/or group B). A preamble group may comprise one or morepreambles. The UE may determine the preamble group based on a pathlossmeasurement and/or a size of the Msg 3 1313. The UE may measure an RSRPof one or more reference signals (e.g., SSBs and/or CSI-RSs) anddetermine at least one reference signal having an RSRP above an RSRPthreshold (e.g., rsrp-ThresholdSSB and/or rsrp-ThresholdCSI-RS). The UEmay select at least one preamble associated with the one or morereference signals and/or a selected preamble group, for example, if theassociation between the one or more preambles and the at least onereference signal is configured by an RRC message.

The UE may determine the preamble based on the one or more RACHparameters provided in the configuration message 1310. For example, theUE may determine the preamble based on a pathloss measurement, an RSRPmeasurement, and/or a size of the Msg 3 1313. As another example, theone or more RACH parameters may indicate: a preamble format; a maximumnumber of preamble transmissions; and/or one or more thresholds fordetermining one or more preamble groups (e.g., group A and group B). Abase station may use the one or more RACH parameters to configure the UEwith an association between one or more preambles and one or morereference signals (e.g., SSBs and/or CSI-RSs). If the association isconfigured, the UE may determine the preamble to include in Msg 1 1311based on the association. The Msg 1 1311 may be transmitted to the basestation via one or more PRACH occasions. The UE may use one or morereference signals (e.g., SSBs and/or CSI-RSs) for selection of thepreamble and for determining of the PRACH occasion. One or more RACHparameters (e.g., ra-ssb-OccasionMskIndex and/or ra-OccasionList) mayindicate an association between the PRACH occasions and the one or morereference signals.

The UE may perform a preamble retransmission if no response is receivedfollowing a preamble transmission. The UE may increase an uplinktransmit power for the preamble retransmission. The UE may select aninitial preamble transmit power based on a pathloss measurement and/or atarget received preamble power configured by the network. The UE maydetermine to retransmit a preamble and may ramp up the uplink transmitpower. The UE may receive one or more RACH parameters (e.g.,PREAMBLE_POWER_RAMPING_STEP) indicating a ramping step for the preambleretransmission. The ramping step may be an amount of incrementalincrease in uplink transmit power for a retransmission. The UE may rampup the uplink transmit power if the UE determines a reference signal(e.g., SSB and/or CSI-RS) that is the same as a previous preambletransmission. The UE may count a number of preamble transmissions and/orretransmissions (e.g., PREAMBLE_TRANSMISSION_COUNTER). The UE maydetermine that a random access procedure completed unsuccessfully, forexample, if the number of preamble transmissions exceeds a thresholdconfigured by the one or more RACH parameters (e.g., preambleTransMax).

The Msg 2 1312 received by the UE may include an RAR. In some scenarios,the Msg 2 1312 may include multiple RARs corresponding to multiple UEs.The Msg 2 1312 may be received after or in response to the transmittingof the Msg 1 1311. The Msg 2 1312 may be scheduled on the DL-SCH andindicated on a PDCCH using a random access RNTI (RA-RNTI). The Msg 21312 may indicate that the Msg 1 1311 was received by the base station.The Msg 2 1312 may include a time-alignment command that may be used bythe UE to adjust the UE's transmission timing, a scheduling grant fortransmission of the Msg 3 1313, and/or a Temporary Cell RNTI (TC-RNTI).After transmitting a preamble, the UE may start a time window (e.g.,ra-ResponseWindow) to monitor a PDCCH for the Msg 2 1312. The UE maydetermine when to start the time window based on a PRACH occasion thatthe UE uses to transmit the preamble. For example, the UE may start thetime window one or more symbols after a last symbol of the preamble(e.g., at a first PDCCH occasion from an end of a preambletransmission). The one or more symbols may be determined based on anumerology. The PDCCH may be in a common search space (e.g., aType1-PDCCH common search space) configured by an RRC message. The UEmay identify the RAR based on a Radio Network Temporary Identifier(RNTI). RNTIs may be used depending on one or more events initiating therandom access procedure. The UE may use random access RNTI (RA-RNTI).The RA-RNTI may be associated with PRACH occasions in which the UEtransmits a preamble. For example, the UE may determine the RA-RNTIbased on: an OFDM symbol index; a slot index; a frequency domain index;and/or a UL carrier indicator of the PRACH occasions. An example ofRA-RNTI may be as follows:

RA-RNTI=1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id,

where s_id may be an index of a first OFDM symbol of the PRACH occasion(e.g., 0≤s_id≤14), t_id may be an index of a first slot of the PRACHoccasion in a system frame (e.g., 0≤t_id≤80), f_id may be an index ofthe PRACH occasion in the frequency domain (e.g., 0≤fid≤8), andul_carrier_id may be a UL carrier used for a preamble transmission(e.g., 0 for an NUL carrier, and 1 for an SUL carrier).The UE may transmit the Msg 3 1313 in response to a successful receptionof the Msg 2 1312 (e.g., using resources identified in the Msg 2 1312).The Msg 3 1313 may be used for contention resolution in, for example,the contention-based random access procedure illustrated in FIG. 13A. Insome scenarios, a plurality of UEs may transmit a same preamble to abase station and the base station may provide an RAR that corresponds toa UE. Collisions may occur if the plurality of UEs interpret the RAR ascorresponding to themselves. Contention resolution (e.g., using the Msg3 1313 and the Msg 4 1314) may be used to increase the likelihood thatthe UE does not incorrectly use an identity of another the UE. Toperform contention resolution, the UE may include a device identifier inthe Msg 3 1313 (e.g., a C-RNTI if assigned, a TC-RNTI included in theMsg 2 1312, and/or any other suitable identifier).

The Msg 4 1314 may be received after or in response to the transmittingof the Msg 3 1313. If a C-RNTI was included in the Msg 3 1313, the basestation will address the UE on the PDCCH using the C-RNTI. If the UE'sunique C-RNTI is detected on the PDCCH, the random access procedure isdetermined to be successfully completed. If a TC-RNTI is included in theMsg 3 1313 (e.g., if the UE is in an RRC_IDLE state or not otherwiseconnected to the base station), Msg 4 1314 will be received using aDL-SCH associated with the TC-RNTI. If a MAC PDU is successfully decodedand a MAC PDU comprises the UE contention resolution identity MAC CEthat matches or otherwise corresponds with the CCCH SDU sent (e.g.,transmitted) in Msg 3 1313, the UE may determine that the contentionresolution is successful and/or the UE may determine that the randomaccess procedure is successfully completed.

The UE may be configured with a supplementary uplink (SUL) carrier and anormal uplink (NUL) carrier. An initial access (e.g., random accessprocedure) may be supported in an uplink carrier. For example, a basestation may configure the UE with two separate RACH configurations: onefor an SUL carrier and the other for an NUL carrier. For random accessin a cell configured with an SUL carrier, the network may indicate whichcarrier to use (NUL or SUL). The UE may determine the SUL carrier, forexample, if a measured quality of one or more reference signals is lowerthan a broadcast threshold. Uplink transmissions of the random accessprocedure (e.g., the Msg 1 1311 and/or the Msg 3 1313) may remain on theselected carrier. The UE may switch an uplink carrier during the randomaccess procedure (e.g., between the Msg 1 1311 and the Msg 3 1313) inone or more cases. For example, the UE may determine and/or switch anuplink carrier for the Msg 1 1311 and/or the Msg 3 1313 based on achannel clear assessment (e.g., a listen-before-talk).

FIG. 13B illustrates a two-step contention-free random access procedure.Similar to the four-step contention-based random access procedureillustrated in FIG. 13A, a base station may, prior to initiation of theprocedure, transmit a configuration message 1320 to the UE. Theconfiguration message 1320 may be analogous in some respects to theconfiguration message 1310. The procedure illustrated in FIG. 13Bcomprises transmission of two messages: a Msg 1 1321 and a Msg 2 1322.The Msg 1 1321 and the Msg 2 1322 may be analogous in some respects tothe Msg 1 1311 and a Msg 2 1312 illustrated in FIG. 13A, respectively.As will be understood from FIGS. 13A and 13B, the contention-free randomaccess procedure may not include messages analogous to the Msg 3 1313and/or the Msg 4 1314.

The contention-free random access procedure illustrated in FIG. 13B maybe initiated for a beam failure recovery, other SI request, SCelladdition, and/or handover. For example, a base station may indicate orassign to the UE the preamble to be used for the Msg 1 1321. The UE mayreceive, from the base station via PDCCH and/or RRC, an indication of apreamble (e.g., ra-PreambleIndex).

After transmitting a preamble, the UE may start a time window (e.g.,ra-ResponseWindow) to monitor a PDCCH for the RAR. In the event of abeam failure recovery request, the base station may configure the UEwith a separate time window and/or a separate PDCCH in a search spaceindicated by an RRC message (e.g., recoverySearchSpaceId). The UE maymonitor for a PDCCH transmission addressed to a Cell RNTI (C-RNTI) onthe search space. In the contention-free random access procedureillustrated in FIG. 13B, the UE may determine that a random accessprocedure successfully completes after or in response to transmission ofMsg 1 1321 and reception of a corresponding Msg 2 1322. The UE maydetermine that a random access procedure successfully completes, forexample, if a PDCCH transmission is addressed to a C-RNTI. The UE maydetermine that a random access procedure successfully completes, forexample, if the UE receives an RAR comprising a preamble identifiercorresponding to a preamble transmitted by the UE and/or the RARcomprises a MAC sub-PDU with the preamble identifier. The UE maydetermine the response as an indication of an acknowledgement for an SIrequest.

FIG. 13C illustrates another two-step random access procedure. Similarto the random access procedures illustrated in FIGS. 13A and 13B, a basestation may, prior to initiation of the procedure, transmit aconfiguration message 1330 to the UE. The configuration message 1330 maybe analogous in some respects to the configuration message 1310 and/orthe configuration message 1320. The procedure illustrated in FIG. 13Ccomprises transmission of two messages: a Msg A 1331 and a Msg B 1332.

Msg A 1331 may be transmitted in an uplink transmission by the UE. Msg A1331 may comprise one or more transmissions of a preamble 1341 and/orone or more transmissions of a transport block 1342. The transport block1342 may comprise contents that are similar and/or equivalent to thecontents of the Msg 3 1313 illustrated in FIG. 13A. The transport block1342 may comprise UCI (e.g., an SR, a HARQ ACK/NACK, and/or the like).The UE may receive the Msg B 1332 after or in response to transmittingthe Msg A 1331. The Msg B 1332 may comprise contents that are similarand/or equivalent to the contents of the Msg 2 1312 (e.g., an RAR)illustrated in FIGS. 13A and 13B and/or the Msg 4 1314 illustrated inFIG. 13A.

The UE may initiate the two-step random access procedure in FIG. 13C forlicensed spectrum and/or unlicensed spectrum. The UE may determine,based on one or more factors, whether to initiate the two-step randomaccess procedure. The one or more factors may be: a radio accesstechnology in use (e.g., LTE, NR, and/or the like); whether the UE hasvalid TA or not; a cell size; the UE's RRC state; a type of spectrum(e.g., licensed vs. unlicensed); and/or any other suitable factors.

The UE may determine, based on two-step RACH parameters included in theconfiguration message 1330, a radio resource and/or an uplink transmitpower for the preamble 1341 and/or the transport block 1342 included inthe Msg A 1331. The RACH parameters may indicate a modulation and codingschemes (MCS), a time-frequency resource, and/or a power control for thepreamble 1341 and/or the transport block 1342. A time-frequency resourcefor transmission of the preamble 1341 (e.g., a PRACH) and atime-frequency resource for transmission of the transport block 1342(e.g., a PUSCH) may be multiplexed using FDM, TDM, and/or CDM. The RACHparameters may enable the UE to determine a reception timing and adownlink channel for monitoring for and/or receiving Msg B 1332.

The transport block 1342 may comprise data (e.g., delay-sensitive data),an identifier of the UE, security information, and/or device information(e.g., an International Mobile Subscriber Identity (IMSI)). The basestation may transmit the Msg B 1332 as a response to the Msg A 1331. TheMsg B 1332 may comprise at least one of following: a preambleidentifier; a timing advance command; a power control command; an uplinkgrant (e.g., a radio resource assignment and/or an MCS); a UE identifierfor contention resolution; and/or an RNTI (e.g., a C-RNTI or a TC-RNTI).The UE may determine that the two-step random access procedure issuccessfully completed if: a preamble identifier in the Msg B 1332 ismatched to a preamble transmitted by the UE; and/or the identifier ofthe UE in Msg B 1332 is matched to the identifier of the UE in the Msg A1331 (e.g., the transport block 1342).

A UE and a base station may exchange control signaling. The controlsignaling may be referred to as L1/L2 control signaling and mayoriginate from the PHY layer (e.g., layer 1) and/or the MAC layer (e.g.,layer 2). The control signaling may comprise downlink control signalingtransmitted from the base station to the UE and/or uplink controlsignaling transmitted from the UE to the base station.

The downlink control signaling may comprise: a downlink schedulingassignment; an uplink scheduling grant indicating uplink radio resourcesand/or a transport format; a slot format information; a preemptionindication; a power control command; and/or any other suitablesignaling. The UE may receive the downlink control signaling in apayload transmitted by the base station on a physical downlink controlchannel (PDCCH). The payload transmitted on the PDCCH may be referred toas downlink control information (DCI). In some scenarios, the PDCCH maybe a group common PDCCH (GC-PDCCH) that is common to a group of UEs.

A base station may attach one or more cyclic redundancy check (CRC)parity bits to a DCI in order to facilitate detection of transmissionerrors. When the DCI is intended for a UE (or a group of the UEs), thebase station may scramble the CRC parity bits with an identifier of theUE (or an identifier of the group of the UEs). Scrambling the CRC paritybits with the identifier may comprise Modulo-2 addition (or an exclusiveOR operation) of the identifier value and the CRC parity bits. Theidentifier may comprise a 16-bit value of a radio network temporaryidentifier (RNTI).

DCIs may be used for different purposes. A purpose may be indicated bythe type of RNTI used to scramble the CRC parity bits. For example, aDCI having CRC parity bits scrambled with a paging RNTI (P-RNTI) mayindicate paging information and/or a system information changenotification. The P-RNTI may be predefined as “FFFE” in hexadecimal. ADCI having CRC parity bits scrambled with a system information RNTI(SI-RNTI) may indicate a broadcast transmission of the systeminformation. The SI-RNTI may be predefined as “FFFF” in hexadecimal. ADCI having CRC parity bits scrambled with a random access RNTI (RA-RNTI)may indicate a random access response (RAR). A DCI having CRC paritybits scrambled with a cell RNTI (C-RNTI) may indicate a dynamicallyscheduled unicast transmission and/or a triggering of PDCCH-orderedrandom access. A DCI having CRC parity bits scrambled with a temporarycell RNTI (TC-RNTI) may indicate a contention resolution (e.g., a Msg 3analogous to the Msg 3 1313 illustrated in FIG. 13A). Other RNTIsconfigured to the UE by a base station may comprise a ConfiguredScheduling RNTI (CS-RNTI), a Transmit Power Control-PUCCH RNTI(TPC-PUCCH-RNTI), a Transmit Power Control-PUSCH RNTI (TPC-PUSCH-RNTI),a Transmit Power Control-SRS RNTI (TPC-SRS-RNTI), an Interruption RNTI(INT-RNTI), a Slot Format Indication RNTI (SFI-RNTI), a Semi-PersistentCSI RNTI (SP-CSI-RNTI), a Modulation and Coding Scheme Cell RNTI(MCS-C-RNTI), and/or the like.

Depending on the purpose and/or content of a DCI, the base station maytransmit the DCIs with one or more DCI formats. For example, DCI format0_0 may be used for scheduling of PUSCH in a cell. DCI format 0_0 may bea fallback DCI format (e.g., with compact DCI payloads). DCI format 0_1may be used for scheduling of PUSCH in a cell (e.g., with more DCIpayloads than DCI format 0_0). DCI format 1_0 may be used for schedulingof PDSCH in a cell. DCI format 1_0 may be a fallback DCI format (e.g.,with compact DCI payloads). DCI format 1_1 may be used for scheduling ofPDSCH in a cell (e.g., with more DCI payloads than DCI format 1_0). DCIformat 2_0 may be used for providing a slot format indication to a groupof UEs. DCI format 2_1 may be used for notifying a group of UEs of aphysical resource block and/or OFDM symbol where the UE may assume notransmission is intended to the UE. DCI format 2_2 may be used fortransmission of a transmit power control (TPC) command for PUCCH orPUSCH. DCI format 2_3 may be used for transmission of a group of TPCcommands for SRS transmissions by one or more UEs. DCI format(s) for newfunctions may be defined in future releases. DCI formats may havedifferent DCI sizes, or may share the same DCI size.

After scrambling a DCI with a RNTI, the base station may process the DCIwith channel coding (e.g., polar coding), rate matching, scramblingand/or QPSK modulation. A base station may map the coded and modulatedDCI on resource elements used and/or configured for a PDCCH. Based on apayload size of the DCI and/or a coverage of the base station, the basestation may transmit the DCI via a PDCCH occupying a number ofcontiguous control channel elements (CCEs). The number of the contiguousCCEs (referred to as aggregation level) may be 1, 2, 4, 8, 16, and/orany other suitable number. A CCE may comprise a number (e.g., 6) ofresource-element groups (REGs). A REG may comprise a resource block inan OFDM symbol. The mapping of the coded and modulated DCI on theresource elements may be based on mapping of CCEs and REGs (e.g.,CCE-to-REG mapping).

FIG. 14A illustrates an example of CORESET configurations for abandwidth part. The base station may transmit a DCI via a PDCCH on oneor more control resource sets (CORESETs). A CORESET may comprise atime-frequency resource in which the UE tries to decode a DCI using oneor more search spaces. The base station may configure a CORESET in thetime-frequency domain. In the example of FIG. 14A, a first CORESET 1401and a second CORESET 1402 occur at the first symbol in a slot. The firstCORESET 1401 overlaps with the second CORESET 1402 in the frequencydomain. A third CORESET 1403 occurs at a third symbol in the slot. Afourth CORESET 1404 occurs at the seventh symbol in the slot. CORESETsmay have a different number of resource blocks in frequency domain.

FIG. 14B illustrates an example of a CCE-to-REG mapping for DCItransmission on a CORESET and PDCCH processing. The CCE-to-REG mappingmay be an interleaved mapping (e.g., for the purpose of providingfrequency diversity) or a non-interleaved mapping (e.g., for thepurposes of facilitating interference coordination and/orfrequency-selective transmission of control channels). The base stationmay perform different or same CCE-to-REG mapping on different CORESETs.A CORESET may be associated with a CCE-to-REG mapping by RRCconfiguration. A CORESET may be configured with an antenna port quasico-location (QCL) parameter. The antenna port QCL parameter may indicateQCL information of a demodulation reference signal (DMRS) for PDCCHreception in the CORESET.

The base station may transmit, to the UE, RRC messages comprisingconfiguration parameters of one or more CORESETs and one or more searchspace sets. The configuration parameters may indicate an associationbetween a search space set and a CORESET. A search space set maycomprise a set of PDCCH candidates formed by CCEs at a given aggregationlevel. The configuration parameters may indicate: a number of PDCCHcandidates to be monitored per aggregation level; a PDCCH monitoringperiodicity and a PDCCH monitoring pattern; one or more DCI formats tobe monitored by the UE; and/or whether a search space set is a commonsearch space set or a UE-specific search space set. A set of CCEs in thecommon search space set may be predefined and known to the UE. A set ofCCEs in the UE-specific search space set may be configured based on theUE's identity (e.g., C-RNTI).

As shown in FIG. 14B, the UE may determine a time-frequency resource fora CORESET based on RRC messages. The UE may determine a CCE-to-REGmapping (e.g., interleaved or non-interleaved, and/or mappingparameters) for the CORESET based on configuration parameters of theCORESET. The UE may determine a number (e.g., at most 10) of searchspace sets configured on the CORESET based on the RRC messages. The UEmay monitor a set of PDCCH candidates according to configurationparameters of a search space set. The UE may monitor a set of PDCCHcandidates in one or more CORESETs for detecting one or more DCIs.Monitoring may comprise decoding one or more PDCCH candidates of the setof the PDCCH candidates according to the monitored DCI formats.Monitoring may comprise decoding a DCI content of one or more PDCCHcandidates with possible (or configured) PDCCH locations, possible (orconfigured) PDCCH formats (e.g., number of CCEs, number of PDCCHcandidates in common search spaces, and/or number of PDCCH candidates inthe UE-specific search spaces) and possible (or configured) DCI formats.The decoding may be referred to as blind decoding. The UE may determinea DCI as valid for the UE, in response to CRC checking (e.g., scrambledbits for CRC parity bits of the DCI matching a RNTI value). The UE mayprocess information contained in the DCI (e.g., a scheduling assignment,an uplink grant, power control, a slot format indication, a downlinkpreemption, and/or the like).

The UE may transmit uplink control signaling (e.g., uplink controlinformation (UCI)) to a base station. The uplink control signaling maycomprise hybrid automatic repeat request (HARQ) acknowledgements forreceived DL-SCH transport blocks. The UE may transmit the HARQacknowledgements after receiving a DL-SCH transport block. Uplinkcontrol signaling may comprise channel state information (CSI)indicating channel quality of a physical downlink channel. The UE maytransmit the CSI to the base station. The base station, based on thereceived CSI, may determine transmission format parameters (e.g.,comprising multi-antenna and beamforming schemes) for a downlinktransmission. Uplink control signaling may comprise scheduling requests(SR). The UE may transmit an SR indicating that uplink data is availablefor transmission to the base station. The UE may transmit a UCI (e.g.,HARQ acknowledgements (HARQ-ACK), CSI report, SR, and the like) via aphysical uplink control channel (PUCCH) or a physical uplink sharedchannel (PUSCH). The UE may transmit the uplink control signaling via aPUCCH using one of several PUCCH formats.

There may be five PUCCH formats and the UE may determine a PUCCH formatbased on a size of the UCI (e.g., a number of uplink symbols of UCItransmission and a number of UCI bits). PUCCH format 0 may have a lengthof one or two OFDM symbols and may include two or fewer bits. The UE maytransmit UCI in a PUCCH resource using PUCCH format 0 if thetransmission is over one or two symbols and the number of HARQ-ACKinformation bits with positive or negative SR (HARQ-ACK/SR bits) is oneor two. PUCCH format 1 may occupy a number between four and fourteenOFDM symbols and may include two or fewer bits. The UE may use PUCCHformat 1 if the transmission is four or more symbols and the number ofHARQ-ACK/SR bits is one or two. PUCCH format 2 may occupy one or twoOFDM symbols and may include more than two bits. The UE may use PUCCHformat 2 if the transmission is over one or two symbols and the numberof UCI bits is two or more. PUCCH format 3 may occupy a number betweenfour and fourteen OFDM symbols and may include more than two bits. TheUE may use PUCCH format 3 if the transmission is four or more symbols,the number of UCI bits is two or more and PUCCH resource does notinclude an orthogonal cover code. PUCCH format 4 may occupy a numberbetween four and fourteen OFDM symbols and may include more than twobits. The UE may use PUCCH format 4 if the transmission is four or moresymbols, the number of UCI bits is two or more and the PUCCH resourceincludes an orthogonal cover code.

The base station may transmit configuration parameters to the UE for aplurality of PUCCH resource sets using, for example, an RRC message. Theplurality of PUCCH resource sets (e.g., up to four sets) may beconfigured on an uplink BWP of a cell. A PUCCH resource set may beconfigured with a PUCCH resource set index, a plurality of PUCCHresources with a PUCCH resource being identified by a PUCCH resourceidentifier (e.g., pucch-Resourceid), and/or a number (e.g. a maximumnumber) of UCI information bits the UE may transmit using one of theplurality of PUCCH resources in the PUCCH resource set. When configuredwith a plurality of PUCCH resource sets, the UE may select one of theplurality of PUCCH resource sets based on a total bit length of the UCIinformation bits (e.g., HARQ-ACK, SR, and/or CSI). If the total bitlength of UCI information bits is two or fewer, the UE may select afirst PUCCH resource set having a PUCCH resource set index equal to “0”.If the total bit length of UCI information bits is greater than two andless than or equal to a first configured value, the UE may select asecond PUCCH resource set having a PUCCH resource set index equal to“1”. If the total bit length of UCI information bits is greater than thefirst configured value and less than or equal to a second configuredvalue, the UE may select a third PUCCH resource set having a PUCCHresource set index equal to “2”. If the total bit length of UCIinformation bits is greater than the second configured value and lessthan or equal to a third value (e.g., 1406), the UE may select a fourthPUCCH resource set having a PUCCH resource set index equal to “3”.

After determining a PUCCH resource set from a plurality of PUCCHresource sets, the UE may determine a PUCCH resource from the PUCCHresource set for UCI (HARQ-ACK, CSI, and/or SR) transmission. The UE maydetermine the PUCCH resource based on a PUCCH resource indicator in aDCI (e.g., with a DCI format 1_0 or DCI for 1_1) received on a PDCCH. Athree-bit PUCCH resource indicator in the DCI may indicate one of eightPUCCH resources in the PUCCH resource set. Based on the PUCCH resourceindicator, the UE may transmit the UCI (HARQ-ACK, CSI and/or SR) using aPUCCH resource indicated by the PUCCH resource indicator in the DCI.

FIG. 15 illustrates an example of a wireless device 1502 incommunication with a base station 1504 in accordance with embodiments ofthe present disclosure. The wireless device 1502 and base station 1504may be part of a mobile communication network, such as the mobilecommunication network 100 illustrated in FIG. 1A, the mobilecommunication network 150 illustrated in FIG. 1B, or any othercommunication network. Only one wireless device 1502 and one basestation 1504 are illustrated in FIG. 15 , but it will be understood thata mobile communication network may include more than one UE and/or morethan one base station, with the same or similar configuration as thoseshown in FIG. 15 .

The base station 1504 may connect the wireless device 1502 to a corenetwork (not shown) through radio communications over the air interface(or radio interface) 1506. The communication direction from the basestation 1504 to the wireless device 1502 over the air interface 1506 isknown as the downlink, and the communication direction from the wirelessdevice 1502 to the base station 1504 over the air interface is known asthe uplink. Downlink transmissions may be separated from uplinktransmissions using FDD, TDD, and/or some combination of the twoduplexing techniques.

In the downlink, data to be sent to the wireless device 1502 from thebase station 1504 may be provided to the processing system 1508 of thebase station 1504. The data may be provided to the processing system1508 by, for example, a core network. In the uplink, data to be sent tothe base station 1504 from the wireless device 1502 may be provided tothe processing system 1518 of the wireless device 1502. The processingsystem 1508 and the processing system 1518 may implement layer 3 andlayer 2 OSI functionality to process the data for transmission. Layer 2may include an SDAP layer, a PDCP layer, an RLC layer, and a MAC layer,for example, with respect to FIG. 2A, FIG. 2B, FIG. 3 , and FIG. 4A.Layer 3 may include an RRC layer as with respect to FIG. 2B.

After being processed by processing system 1508, the data to be sent tothe wireless device 1502 may be provided to a transmission processingsystem 1510 of base station 1504. Similarly, after being processed bythe processing system 1518, the data to be sent to base station 1504 maybe provided to a transmission processing system 1520 of the wirelessdevice 1502. The transmission processing system 1510 and thetransmission processing system 1520 may implement layer 1 OSIfunctionality. Layer 1 may include a PHY layer with respect to FIG. 2A,FIG. 2B, FIG. 3 , and FIG. 4A. For transmit processing, the PHY layermay perform, for example, forward error correction coding of transportchannels, interleaving, rate matching, mapping of transport channels tophysical channels, modulation of physical channel, multiple-inputmultiple-output (MIMO) or multi-antenna processing, and/or the like.

At the base station 1504, a reception processing system 1512 may receivethe uplink transmission from the wireless device 1502. At the wirelessdevice 1502, a reception processing system 1522 may receive the downlinktransmission from base station 1504. The reception processing system1512 and the reception processing system 1522 may implement layer 1 OSIfunctionality. Layer 1 may include a PHY layer with respect to FIG. 2A,FIG. 2B, FIG. 3 , and FIG. 4A. For receive processing, the PHY layer mayperform, for example, error detection, forward error correctiondecoding, deinterleaving, demapping of transport channels to physicalchannels, demodulation of physical channels, MIMO or multi-antennaprocessing, and/or the like.

As shown in FIG. 15 , a wireless device 1502 and the base station 1504may include multiple antennas. The multiple antennas may be used toperform one or more MIMO or multi-antenna techniques, such as spatialmultiplexing (e.g., single-user MIMO or multi-user MIMO),transmit/receive diversity, and/or beamforming. In other examples, thewireless device 1502 and/or the base station 1504 may have a singleantenna.

The processing system 1508 and the processing system 1518 may beassociated with a memory 1514 and a memory 1524, respectively. Memory1514 and memory 1524 (e.g., one or more non-transitory computer readablemediums) may store computer program instructions or code that may beexecuted by the processing system 1508 and/or the processing system 1518to carry out one or more of the functionalities discussed in the presentapplication. Although not shown in FIG. 15 , the transmission processingsystem 1510, the transmission processing system 1520, the receptionprocessing system 1512, and/or the reception processing system 1522 maybe coupled to a memory (e.g., one or more non-transitory computerreadable mediums) storing computer program instructions or code that maybe executed to carry out one or more of their respectivefunctionalities.

The processing system 1508 and/or the processing system 1518 maycomprise one or more controllers and/or one or more processors. The oneor more controllers and/or one or more processors may comprise, forexample, a general-purpose processor, a digital signal processor (DSP),a microcontroller, an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) and/or other programmable logicdevice, discrete gate and/or transistor logic, discrete hardwarecomponents, an on-board unit, or any combination thereof. The processingsystem 1508 and/or the processing system 1518 may perform at least oneof signal coding/processing, data processing, power control,input/output processing, and/or any other functionality that may enablethe wireless device 1502 and the base station 1504 to operate in awireless environment.

The processing system 1508 and/or the processing system 1518 may beconnected to one or more peripherals 1516 and one or more peripherals1526, respectively. The one or more peripherals 1516 and the one or moreperipherals 1526 may include software and/or hardware that providefeatures and/or functionalities, for example, a speaker, a microphone, akeypad, a display, a touchpad, a power source, a satellite transceiver,a universal serial bus (USB) port, a hands-free headset, a frequencymodulated (FM) radio unit, a media player, an Internet browser, anelectronic control unit (e.g., for a motor vehicle), and/or one or moresensors (e.g., an accelerometer, a gyroscope, a temperature sensor, aradar sensor, a lidar sensor, an ultrasonic sensor, a light sensor, acamera, and/or the like). The processing system 1508 and/or theprocessing system 1518 may receive user input data from and/or provideuser output data to the one or more peripherals 1516 and/or the one ormore peripherals 1526. The processing system 1518 in the wireless device1502 may receive power from a power source and/or may be configured todistribute the power to the other components in the wireless device1502. The power source may comprise one or more sources of power, forexample, a battery, a solar cell, a fuel cell, or any combinationthereof. The processing system 1508 and/or the processing system 1518may be connected to a GPS chipset 1517 and a GPS chipset 1527,respectively. The GPS chipset 1517 and the GPS chipset 1527 may beconfigured to provide geographic location information of the wirelessdevice 1502 and the base station 1504, respectively.

FIG. 16A illustrates an example structure for uplink transmission. Abaseband signal representing a physical uplink shared channel mayperform one or more functions. The one or more functions may comprise atleast one of: scrambling; modulation of scrambled bits to generatecomplex-valued symbols; mapping of the complex-valued modulation symbolsonto one or several transmission layers; transform precoding to generatecomplex-valued symbols; precoding of the complex-valued symbols; mappingof precoded complex-valued symbols to resource elements; generation ofcomplex-valued time-domain Single Carrier-Frequency Division MultipleAccess (SC-FDMA) or CP-OFDM signal for an antenna port; and/or the like.In an example, when transform precoding is enabled, a SC-FDMA signal foruplink transmission may be generated. In an example, when transformprecoding is not enabled, an CP-OFDM signal for uplink transmission maybe generated by FIG. 16A. These functions are illustrated as examplesand it is anticipated that other mechanisms may be implemented invarious embodiments.

FIG. 16B illustrates an example structure for modulation andup-conversion of a baseband signal to a carrier frequency. The basebandsignal may be a complex-valued SC-FDMA or CP-OFDM baseband signal for anantenna port and/or a complex-valued Physical Random Access Channel(PRACH) baseband signal. Filtering may be employed prior totransmission.

FIG. 16C illustrates an example structure for downlink transmissions. Abaseband signal representing a physical downlink channel may perform oneor more functions. The one or more functions may comprise: scrambling ofcoded bits in a codeword to be transmitted on a physical channel;modulation of scrambled bits to generate complex-valued modulationsymbols; mapping of the complex-valued modulation symbols onto one orseveral transmission layers; precoding of the complex-valued modulationsymbols on a layer for transmission on the antenna ports; mapping ofcomplex-valued modulation symbols for an antenna port to resourceelements; generation of complex-valued time-domain OFDM signal for anantenna port; and/or the like. These functions are illustrated asexamples and it is anticipated that other mechanisms may be implementedin various embodiments.

FIG. 16D illustrates another example structure for modulation andup-conversion of a baseband signal to a carrier frequency. The basebandsignal may be a complex-valued OFDM baseband signal for an antenna port.Filtering may be employed prior to transmission.

A wireless device may receive from a base station one or more messages(e.g. RRC messages) comprising configuration parameters of a pluralityof cells (e.g. primary cell, secondary cell). The wireless device maycommunicate with at least one base station (e.g. two or more basestations in dual-connectivity) via the plurality of cells. The one ormore messages (e.g. as a part of the configuration parameters) maycomprise parameters of physical, MAC, RLC, PCDP, SDAP, RRC layers forconfiguring the wireless device. For example, the configurationparameters may comprise parameters for configuring physical and MAClayer channels, bearers, etc. For example, the configuration parametersmay comprise parameters indicating values of timers for physical, MAC,RLC, PCDP, SDAP, RRC layers, and/or communication channels.

A timer may begin running once it is started and continue running untilit is stopped or until it expires. A timer may be started if it is notrunning or restarted if it is running. A timer may be associated with avalue (e.g. the timer may be started or restarted from a value or may bestarted from zero and expire once it reaches the value). The duration ofa timer may not be updated until the timer is stopped or expires (e.g.,due to BWP switching). A timer may be used to measure a timeperiod/window for a process. When the specification refers to animplementation and procedure related to one or more timers, it will beunderstood that there are multiple ways to implement the one or moretimers. For example, it will be understood that one or more of themultiple ways to implement a timer may be used to measure a timeperiod/window for the procedure. For example, a random access responsewindow timer may be used for measuring a window of time for receiving arandom access response. In an example, instead of starting and expiry ofa random access response window timer, the time difference between twotime stamps may be used. When a timer is restarted, a process formeasurement of time window may be restarted. Other exampleimplementations may be provided to restart a measurement of a timewindow.

For a two-step RA procedure, a wireless device may receive, from a basestation, one or more RRC messages comprising two-step RACH configurationparameters 1330. The one or more RRC messages may broadcast (e.g., viasystem information broadcast messages), multicast (e.g., via systeminformation broadcast messages), and/or unicast (e.g., via dedicated RRCmessages and/or lower layer control signal(s) such as PDCCH) to awireless device. The one or more RRC messages may be wirelessdevice-specific messages, e.g., a dedicated RRC message transmitted to awireless device with RRC INACTIVE 604 or RRC CONNECTED 602. The one ormore RRC messages may comprise parameters required for transmitting MsgA 1331. For example, the parameter may indicate at least one offollowing: PRACH resource allocation, preamble format, SSB information(e.g., total number of SSBs, downlink resource allocation of SSBtransmission, transmission power of SSB transmission, uplink radioresources (time-frequency radio resource, DMRS, MCS, etc.) for one ormore transport block transmissions, and/or association between PRACHresource allocation and the uplink radio resources (or associationsbetween the uplink radio resources and downlink reference signals).

In the UL transmission (e.g., Msg A 1331) of a two-step RA procedure, awireless device may transmit, e.g., to a base station, at least oneRandom Access Preamble (RAP) (e.g., Preamble 1341) and/or one or moretransport blocks (e.g., Transport block 1342). For example, the one ormore transport blocks may comprise at least one of data, securityinformation, device information such as IMSI/TMSI, and/or otherinformation. For example, the one or more transport blocks may comprisea wireless device identifier (ID) that may be used for a contentionresolution. In the DL transmission of the two-step RA procedure, a basestation may transmit Msg B 1332 (e.g., a random access responsecorresponding to MsgA 1331) that may comprise at least one of following:a timing advance command indicating the TA value, a power controlcommand, an UL grant (e.g., radio resource assignment, and/or MCS), theidentifier for contention resolution, an RNTI (e.g., C-RNTI or TC-RNTI),and/or other information. The Msg B 1332 may comprise at least one of: apreamble identifier corresponding to the Preamble 1341, a positive ornegative acknowledgement of a reception of the one or more transportblocks 1342, an implicit and/or explicit indication of a successfuldecoding of the one or more transport blocks 1342, an indication offallback to a non-two step RA procedure (e.g., contention-based RAprocedure in FIG. 13A or contention-free RA procedure in FIG. 13B),and/or any combination thereof.

A wireless device may initiate a two step RA procedure. The wirelessdevice may transmit Msg A comprising at least one preamble and/or atleast one transport block. The at least one transport block may comprisean identifier that the wireless device uses for a contention resolution.The identifier may be sequence(s) and/or number(s) that the wirelessdevice generates (e.g., for a case that C-RNTI has not been assigned, bythe base station, to the wireless device). The wireless device maygenerate the identifier randomly and/or generate based on a subscriber,device information of the wireless device (e.g., IMSI/TMSI) and/or aresume identifier assigned by the base station to the wireless device.For example, the identifier may be an extended and/or truncatedsubscriber and/or device information of the wireless device (e.g.,IMSI/TMSI). For example, the identifier is a C-RNTI (e.g., for awireless device with RRC Connected). The wireless device may indicatethe C-RNTI to the base station based on a particular message format thatmay be predefined. For example, the at least one transport blockcomprises an C-RNTI MAC CE (e.g., 16 bits fields indicate the C-RNTI).The wireless device may transmit the C-RNTI MAC CE with an LCID in asubheader corresponding to the C-RNTI MAC CE. For example, the LCID maybe used for a base station to identify (detect, parse, and/or decode)the C-RNTI MAC CE from a received signal or message (e.g., MAC PDU)transmitted from the wireless device.

A wireless device may start to monitor a downlink control channel forMsg B corresponding to the Msg A, e.g., after or in response totransmitting the Msg A. A control resource set and/or a search space formonitoring the downlink control channel may be indicated and/orconfigured by message(s), e.g., broadcast RRC message and/or wirelessdevice specific RRC message, transmitted by a base station. The Msg Bmay be scrambled by a particular RNTI. The wireless device may use anRNTI (e.g., C-RNTI) assigned by the base station as the particular RNTI.The wireless device may determine the particular RNTI based on at leastone of following: a time resource index (e.g., an index of a first OFDMsymbol of and/or an index of a first slot) of PRACH occasion that the atleast one preamble is transmitted, a frequency resource index of PRACHoccasion that the at least one preamble is transmitted, a time resourceindex (e.g., an index of a first OFDM symbol of and/or an index of afirst slot) PUSCH occasion that the at least one transport block istransmitted, a frequency resource index of PUSCH occasion that the atleast one transport block is transmitted, an indicator (e.g., 0 or 1) ofan uplink carrier where the Msg A is transmitted. The wireless devicemay determine (or consider) that the two step RA procedure issuccessfully completed based on one or more conditions. At least one ofthe one or more conditions may be that the Msg B comprises a preambleindex (or identifier) matched to the at least one preamble that thewireless device transmits to the base station. At least one of the oneor more conditions may be that the Msg B comprises and/or indicates acontention resolution identifier matched to the identifier that thewireless device transmits to the base station for the contentionresolution. In an example, the wireless device may receive the Msg Bindicating a retransmission of the at least one transport block. Forexample, the Msg B indicating a retransmission of the at least onetransport block comprises an UL grant indicating uplink resource(s) usedfor the retransmission of the at least one transport block.

In the UL transmission of a two-step RA procedure, a wireless device maytransmit, via a cell and to a base station, at least one RAP and one ormore TBs. The wireless device may receive message(s) one or moreconfiguration parameters for the UL transmission of the two-step RAprocedure, e.g., at step 1330 in FIG. 13 . For example, the one or moreconfiguration parameters may indicate at least one of: PRACHoccasion(s), preamble format, a number of transmitting SSBs, downlinkresources of transmissions of SSB(s), transmission power of SSBtransmission(s), association between each of PRACH occasion(s) and eachof SSB(s), PUSCH resource(s) (in terms of time, frequency,code/sequence/signature) for one or more TB transmissions, associationbetween each of PRACH occasion(s) and each of PUSCH resource(s), and/orpower control parameters of one or more TB transmissions. The powercontrol parameters of one or more TB transmissions may comprise at leastone of following: power parameter value(s) for cell and/or UE specificpower adjustments used for determining a received target power, ascaling factor (e.g., inter-cell interference control parameter) of apathloss measurement, reference signal power used for determining apathloss measurement, a power offset with respect to a power of preambletransmission, and/or one or more power offsets. For example, thewireless device measures received signal power(s) (e.g., RSRP) and/orquality (e.g., RSRQ) of one or more SSBs that a base station transmits.The wireless device may select at least one SSB based on the measurementand determine at least one PRACH occasion associated with the at leastone SSB and/or at least one PUSCH resource associated with the at leastone PRACH occasion and/or associated with the at least one SSB (thisassociation may be configured explicitly by the message(s) and/orimplicitly through a first association between the at least one SSB andthe at least one PRACH occasion and a second association between the atleast one PRACH occasion and the at least one PUSCH resource). Thewireless device may transmit at least one RAP via the at least one PRACHoccasion and/or transmit at least one TB via the at least one PUSCHresource. The wireless device may determine transmit powers of the atleast one RAP and/or the at least one TB based on the configurationparameters indicated by the message(s). For example, the configurationparameters indicate uplink transmit power control parameters comprisingat least one of following: a received target power for a base station,one or more power offsets, power ramping step, power ramping counter,retransmission counter, pathloss reference signal index (or indices),pathloss reference signal reference power. At least one of the uplinktransmit power control parameters may be shared between an uplinktransmit power for the at least one RAP and an uplink transmit power forthe at least one TB. For example, sharing the at least one of the uplinktransmit power control parameter may reduce a size of the message(s)(e.g., comparing with a case that the at least one uplink transmit powercontrol parameter repeats for the at least one RAP and for the at leastone TB in the messages(s)). None of the uplink transmit power controlparameters may be shared between an uplink transmit power for the atleast one RAP and an uplink transmit power for the at least one TB. Amessage structure of the message(s) may be flexible such that a basestation indicates to the wireless device whether at least one of (orwhich one or more of) the uplink transmit power control parameters maybe shared between an uplink transmit power for the at least one RAP andan uplink transmit power for the at least one TB. For example, thewireless device determines, based on the message structure of themessage(s), whether at least one of (or which one or more of) the uplinktransmit power control parameters may be shared between an uplinktransmit power for the at least one RAP and an uplink transmit power forthe at least one TB.

There may be one or more ways for a wireless device to generate one ormore candidate preambles that may be used for a two-step RA procedure.For example, a two-step RACH configuration comprises RAP generatingparameter(s) (e.g., a root sequence), based on which the wireless devicegenerates the one or more candidate preambles. The wireless device may(e.g., randomly) select one of the one or more candidate preambles as anRAP to be used for transmission of Preamble 1341. The RAP generatingparameters may be DL reference signal (e.g., SSB or CSI-RS)-specific,cell-specific, and/or wireless device-specific. For example, the RAPgenerating parameters for a first DL reference signal are different fromthe RAP generating parameters for a second DL reference signal. Forexample, the RAP generating parameters are common for one or more DLreference signals of a cell where a wireless device initiates a two-stepRA procedure. For example, a wireless device receives, from a basestation, a control message (e.g., SIB message, RRC message dedicated toa wireless device, and/or a PDCCH order for a secondary cell addition)that indicates one or more preamble indices of one or more RAPs to beused for a two-step RA procedure of the wireless device. The one or morecandidate preambles may be grouped into one or more groups. For example,each group is associated with a specific amount of data fortransmission. For example, the amount of data indicates a size of one ormore transport blocks that a wireless device to transmit and/orindicates a size of uplink data that remains in the buffer. Each of theone or more groups may be associated with a range of data size. Forexample, a first group of the one or more groups comprises RAPsindicating small data transmission(s) of transport block(s) during thetwo-step RA procedure, and a second group may comprise RAPs indicatinglarger data transmission(s) of transport block(s) during the two-step RAprocedure, and so on. A base station may transmit an RRC messagecomprising one or more thresholds based on which a wireless device maydetermine which group of RAPs the wireless device selects an RAP. Forexample, the one or more thresholds indicate one or more data sizes thatdetermine the one or more groups. Based on a size of uplink data that awireless device potentially transmits to, the wireless device comparesthe size of uplink data with the one or more data sizes and determines aparticular group from the one or more groups. By transmitting an RAPselected from the specific group, the wireless device may indicate, to abase station, a (e.g., estimated) size of uplink data that the wirelessdevice transmits, to the base station. The indication of the size ofuplink data may be used for a base station to determine a proper size ofuplink radio resources for (re)transmission of the uplink data.

In a two-step RA procedure, a wireless device may transmit an RAP via aPRACH occasion indicated by a two-step RACH configuration. The wirelessdevice may transmit one or more TBs via an UL radio resource (e.g.,PUSCH) indicated by a two-step RACH configuration. A first transmissionof the RAP and a second transmission of the one or more TBs may bescheduled in a TDM (time-division multiplexing) manner, a FDM(frequency-division multiplexing) manner, a CDM (code-divisionmultiplexing) manner, and/or any combination thereof. The firsttransmission of the RAP may be overlapped in time (partially orentirely) with the second transmission of the one or more TBs. Thetwo-step RACH configuration may indicate a portion (e.g., in frequencydomain and/or in time domain) of overlapping of radio resources betweenthe RAP and one or more TB transmissions. The first transmission of theRAP may be TDMed without overlapping with the second transmission of theone or more TBs in different frequencies (e.g., PRBs) or in the samefrequency (e.g., PRB). The two-step RACH configuration may indicate oneor more UL radio resources associated with one or more RAPs (or RAPgroups) and/or the PRACH occasion. For example, each of one or moredownlink reference signals (SSBs or CSI-RSs) is associated with one ormore PRACH occasions and/or one or more RAPs. A wireless device maydetermine at least one PRACH occasion among the one or more PRACHoccasions and/or at least one RAP among the one or more RAPs. Forexample, a wireless device measures RSRP and/or RSRQ of the one or moredownlink reference signals and selects a first downlink reference signalfrom the one or more downlink reference signals. For example, an RSRP ofthe first downlink reference signal is larger than a threshold (e.g.,indicated by a base station via a control message or signal). Thewireless device may select at least one RAP and/or at least one PRACHoccasion, that are associated with the first downlink reference signal,as a radio resource for Preamble 1341. Based on a selection of the atleast one RAP and/or the at least one PRACH occasion, the wirelessdevice may determine at least one UL radio resource (e.g., PUSCHoccasions) where the wireless device transmits one or more TBs as a partof a two-step RACH procedure. The wireless device may determine the atleast one UL radio resource (e.g., PUSCH occasions) based on the firstdownlink reference signal, e.g., if a control message and/or a controlsignal that the wireless device received from the base station indicateassociations between one or more UL radio resources (e.g., PUSCHoccasions) and the one or more downlink reference signals.

The one or more UL radio resources may be indicated based on a framestructure in FIG. 7 , and/or OFDM radio structure in FIG. 8 . Forexample, time domain resource(s) of the one or more UL radio resourcesis indicated with respect to a particular SFN (SFN=0), slot number, anOFDM symbol number, and/or a combination thereof. For example, timedomain resource(s) of the one or more UL radio resources is indicatedwith respect to a subcarrier number, a number of resource elements, anumber of resource blocks, RBG number, frequency index for a frequencydomain radio resource, and/or a combination thereof. For example, theone or more UL radio resources may be indicated based on a time offsetand/or a frequency offset with respect to one or more PRACH occasions ofa selected RAP. The UL transmissions may occur, e.g., in the same slot(or subframe) and/or in a different slot, e.g., in consecutive slots (orsubframes). For example, the one or more UL radio resources (e.g., PUSCHoccasions) may be configured periodically, e.g., a periodic resources ofconfigured grant Type 1 or Type 2.

A PUSCH occasion for two-step RA procedure may be an uplink radioresource for a transport block 1342 (e.g., payload) transmissionassociated with a PRACH preamble in MsgA 1331 of two-step RA procedure.One or more examples of a resource allocation of a PUSCH occasion may be(but not limited to) that PUSCH occasions are separately configured fromPRACH occasions. For example, for a PUSCH occasion may be determinedbased on a periodic resource indicated by a configured grant (e.g.,configured grant Type 1/Type 2 and/or SPS). A wireless device maydetermine the PUSCH occasion further based on an association between thePRACH and PUSCH for msgA transmission. For example, a wireless devicemay receive, from a base station, configuration parameters indication atleast one of following: a modulation and coding scheme, a transportblock size, a number of FDMed PUSCH occasions (the FDMed PUSCH occasionsmay comprise guard band and/or guard period, e.g., if exist, and theFDMed PUSCH occasions under the same Msg A PUSCH configurations may beconsecutive in frequency domain), a number of PRBs per PUSCH occasion, anumber of DMRS symbols/ports/sequences per PUSCH occasion, a number ofrepetitions for Msg A PUSCH (Transport block 1342) transmission, abandwidth of PRB level guard band, duration of guard time, a PUSCHmapping type of Transport block 1342, a periodicity (e.g., MsgA PUSCHconfiguration period), offset(s) (e.g., in terms of any combination ofat least one of symbol, slot, subframe, and/or SFN), a time domainresource allocation (e.g., in a slot for MsgA PUSCH: starting symbol, anumber of symbols per PUSCH occasion, a number of time-domain PUSCHoccasions), a frequency starting point.

One or more examples of a resource allocation of a PUSCH occasion may be(but not limited to) that a base station configure a relative location(e.g., in time and/or frequency) of the PUSCH occasion with respect to aPRACH occasion. For example, time and/or frequency relation betweenPRACH preambles in a PRACH occasion and PUSCH occasions may be a singlespecification fixed value. For example, a time and/or frequency relationbetween each PRACH preamble in a PRACH occasion to the PUSCH occasion isa single specification fixed value. For example, different preambles indifferent PRACH occasions have different values. For example, a timeand/or frequency relation between PRACH preambles in a PRACH occasionand PUSCH occasions are single semi-statically configured value. Forexample, a time and/or frequency relation between each PRACH preamble ina PRACH occasion to the PUSCH occasion is semi-statically configuredvalue. For example, different preambles in different PRACH occasionshave different values. For example, any combination of above example maybe implemented/configured, and the time and frequency relation need notbe the same alternative. For example, a wireless device may receive,from a base station, configuration parameters indication at least one offollowing: a modulation and coding scheme, a transport block size, anumber of FDMed PUSCH occasions (the FDMed PUSCH occasions may compriseguard band and/or guard period, e.g., if exist, and the FDMed PUSCHoccasions under the same Msg A PUSCH configurations may be consecutivein frequency domain), a number of PRBs per PUSCH occasion, a number ofDMRS symbols/ports/sequences per PUSCH occasion, a number of repetitionsfor Msg A PUSCH (Transport block 1342) transmission, a bandwidth of PRBlevel guard band, duration of guard time, a PUSCH mapping type ofTransport block 1342, a time offset (e.g., a combination of slot-leveland symbol-level indication) with respect to a reference point (e.g., aparticular SFN, associated PRACH occasion, and/or start or end ofassociated PRACH slot), a number of symbols per PUSCH occasion, a numberof TDMed PUSCH occasions.

For a two-step RA procedure, a resource allocation for a payloadtransmission in a PUSCH occasion may be predefined and/or configured.For example, a size of a resource in a PUSCH occasion may be predefinedand/or configured. The resource may be continuous or non-continuous(e.g., a base station may flexibly configure the resource). The resourcemay be partitioned into a plurality of resource groups. For example, asize of each of resource groups within a PUSCH occasion may be the sameor different (e.g., depending on the configuration of the two-step RAprocedure). Each resource group index may be mapped to one or morepreamble index.

For example, a base station may configure a wireless device with one ormore parameters indicating a starting point of time and/re frequency fora PUSCH occasion, a number of resource groups, and a size of each of theresource groups. An index of each of the resource groups may be mappedto a preamble index (e.g., a particular preamble) and/or a particularPPRACH occasion. The wireless device may determine a location of each ofresource groups at least based on a preamble index (e.g., in case RO andPUSCH occasion are 1-to-1 mapping) and/or based on an RO index and apreamble index (e.g., in the case of multiple ROs are associated withone PUSCH occasion).

A wireless device may receive, from a base station, configurationparameters indicating the starting point of time/frequency for the PUSCHoccasion and/or a set of continuous basic unit of PUSCH resources. Thesize of resource unit may be identical, and the total available numberof basic unit may be pre-configured. A wireless device may use one ormultiple resource unit for the MsgA 1331 transmission, depending on thepayload size. The starting resource unit index may be mapped to preambleindex, and the length of occupied PUSCH resource (as the number ofresource unit) may be either mapped to preamble index or explicitlyindicated (e.g. in UCI).

A number of resource groups and/or the detailed mapping amongpreamble(s), resource group(s), and DMRS port(s) may be pre-definedand/or semi-statically configured (and/or indicated by DCI dynamically),e.g., to avoid a blind detection from a base station when multiplepreambles are mapped to the same resource group.

For a payload transmission via a PUSCHC occasion in a two-step RAprocedure, a wireless device may receive, from a base station,configuration parameters indicating one or more MCSs and one or moreresource sizes for a transmission of payload. The MCS and resource sizemay be related to a size of the payload. For example, the configurationparameters received by the wireless device may indicate one or morecombinations (and/or associations) of a size of the payload, MCS, andresource size. For example, one or more particular modulation types(e.g., pi/2-BPSK, BPSK, QPSK) may be associated with a small size ofpayload. For example, a one or more particular modulation types (e.g.,QPSK) may be used for a wireless device with a particular RRC state(e.g., RRC IDLE and/or RRC INACTIVE). For example, the configurationparameters received by the wireless device may indicate a number of PRBsused for payload transmission over an entire UL BWP and/or over a partof UL BWP (e.g., this may be predefined and/or semi-staticallyconfigured by RRC). The configuration parameters received by thewireless device may indicate one or more repetitions of Transport block1342 (e.g., payload). For example, a number of repetitions ispredefined, semi-statically configured, and/or triggered based on one ormore conditions (e.g., RSRP of downlink reference signals, and/or aparticular RRC state, and/or a type of a wireless device, e.g.,stationary, IoT, etc.) for the coverage enhancement of a transmission ofpayload.

A wireless device may receive, from a base station, one or more two-stepRA configurations for Transport block 1342 (e.g., payload) transmission.The one or more two-step RA configuration may indicate one or morecombinations of payload size, MCS, and/or resource size. The number ofthe one or more two-step RA configurations and one or more parametervalues (e.g., payload size, MCS, and/or resource size) for each of theone or more two-step RA configurations may depend on the content of MsgAand/or an RRC state of a wireless device.

Based on configured two-step RA configuration parameters, a wirelessdevice may transmit MsgA, e.g., comprising at least one preamble via aPRACH occasion and/or a Transport block 1342 (e.g., payload) via a PUSCHoccasion, to a base station. MsgA may comprise an identifier forcontention resolution. For example, a wireless device may construct aMAC header as the msgA payload with a plurality of bits (e.g., 56 and/or72 bits). For example, MsgA may comprise BSR, PHR, RRC messages,connection request, etc. For example, MsgA may comprise UCI. The UCI inMsgA may comprise at least one of following, e.g., if MsgA comprises theUCI: an MCS indication, HARQ-ACK/NACT and/or CSI report. HARQ for MsgAmay combine between an initial transmission of Msg.A and one or moreretransmissions of Msg.A PUSCH. For example, Msg A may indicate atransmission time of MsgA in the PUSCH of MsgA. A size of msgA maydepend on use case.

There may be a case that a wireless device receive, from a base station,configuration parameters indicating different (or independent) PRACHoccasions between two-step RA and four-step RA. The different (orindependent) PRACH occasions may reduce receiver uncertainty and/orreduce the access delay. The base station may configure the wirelessdevice with different (or independent) PRACH resources such that thebase station identifies whether a received preamble is transmitted by awireless device for two-step RA or four-step RA based on PRACH occasionthat the base station receives the received preamble. A base station mayflexibility determine whether to configure shared PRACH occasions orseparate PRACH occasions between two-step RA and four-step RAprocedures. A wireless device may receive, from the base station, RRCmessage(s) and/or DCI indicating an explicit or implicit indication ofwhether to configure shared PRACH occasions or separate PRACH occasionsbetween two-step RA and four-step RA procedures. There may be a casethat a base station configures one or more PRACH occasions sharedbetween two-step RA and four-step RA and preambles partitioned for thetwo-step RA and the four-step RA.

FIG. 17A, FIG. 17B, and FIG. 17C are examples of radio resourceallocations of a PRACH resource and one or more associated UL radioresources based on a time offset, a frequency offset, and a combinationof a time offset and a frequency offset, respectively. For example, aPRACH occasion and one or more associated UL radio resources (e.g.,PUSCH occasions) for MsgA 1331 may be allocated with a time offsetand/or frequency offset, e.g., provided by RRC messages (as a part ofRACH config.) and/or predefined (e.g., as a mapping table). FIG. 17A isan example of a PRACH occasion TDMed with a UL radio resources (e.g.,PUSCH occasion). FIG. 17B is an example of a PRACH occasion FDMed with aUL radio resources (e.g., PUSCH occasion). FIG. 17C is an example of aPRACH occasion TDMed and FDMed with a UL radio resources (e.g., PUSCHoccasion).

A wireless device may receive, from a base station, one or more downlinkreference signals (e.g., SSBs or CSI-RSs), and each of the one or moredownlink reference signals may be associated with one or more RACHresources (e.g., PRACH occasions) and/or one or more UL radio resources(e.g., PUSCH occasions) provided by a two-step RACH configuration. Awireless device may measure one or more downlink reference signals and,based on measured received signal strength and/or quality (or based onother selection rule), may select at least one downlink referencesignals among the one or more downlink reference signals. The wirelessdevice may respectively transmit an RAP (e.g., Preamble 1341) and one ormore TBs (e.g., Transport block 1342) via a PRACH occasion associatedwith the at least one downlink reference signal, and via UL radioresources (e.g., a PUSCH occasions) associated with the PRACH occasionand/or associated with the at least one downlink reference signal.

In an example, a base station may employ an RAP receive from a wirelessdevice to adjust UL transmission timing of one or more TBs for thewireless device in a cell and/or to aid in UL channel estimation for oneor more TBs. A portion of the UL transmission for one or more TBs in atwo-step RACH procedure may comprise, e.g., a wireless device ID, aC-RNTI, a service request such as buffer state reporting (e.g., a bufferstatus report) (BSR), one or more user data packets, and/or otherinformation. A wireless device, e.g., in an RRC CONNECTED 602 state, mayuse a C-RNTI as an identifier of the wireless device (e.g., a wirelessdevice ID). A wireless device, e.g., in an RRC INACTIVE 604 state, mayuse a C-RNTI (if available), a resume ID, or a short MAC-ID as anidentifier of the wireless device. A wireless device, e.g., in an RRCIDLE 606 state, may use a C-RNTI (if available), a resume ID, a shortMAC-ID, an IMSI (International Mobile Subscriber Identifier), a T-IMSI(Temporary-IMSI), and/or a random number (e.g., generated by thewireless device) as an identifier of the wireless device.

In a two-step RA procedure, a wireless device may receive two separateresponses corresponding to Msg A; a first response for RAP (e.g.,Preamble 1342) transmission; and a second response for a transmission ofone or more TBs (e.g., Transport block 1342). A wireless device maymonitor a PDCCH (e.g., common search space and/or a wireless devicespecific search space) to detect the first response with a random accessRNTI generated based on time and/or frequency indices of PRACH resourcewhere the wireless device transmits an RAP. A wireless device maymonitor a common search space and/or a wireless device specific searchspace to detect the second response. The wireless device may employ asecond RNTI to detect the second response. For example, the second RNTIis a C-RNTI if configured, a random access RNTI generated based on timeand/or frequency indices of PRACH occasion where the wireless devicetransmits an RAP, or an RNTI generated based on time and/or frequencyindices (and/or DM-RS ID) of PUSCH resource(s) where the wireless devicetransmits the or more TBs. The wireless device specific search space maybe predefined and/or configured by an RRC message received from a basestation.

A wireless device may trigger (and/or initiate), based on one or moreconditions (e.g., events) a two-step random access procedure. Forexample, one or more conditions (e.g., events) may be at least one of:initial access from RRC_IDLE, RRC connection re-establishment procedure,handover, DL or UL data arrival during RRC_CONNECTED 602 when ULsynchronization status is non-synchronized, transition from RRC INACTIVE604, beam failure recovery procedure, and/or request for other systeminformation. For example, a PDCCH order, an MAC entity of the wirelessdevice, and/or a beam failure indication may initiate a random accessprocedure.

A wireless device may initiate a two-step RA procedure in a particularcondition, e.g., depending on a service of data to be transmitted (e.g.,delay sensitive data such URLLC) and/or radio conditions. For example, abase station may configure one or more wireless devices with a two-stepRA procedure, for example, if a cell is small (e.g., there is no need ofa TA) and/or for a case of stationary wireless device (e.g., there is noneed of TA update). A wireless device may acquire the configuration, viaone or more RRC messages (e.g., MIB, system information blocks,multicast and/or unicast RRC signaling), and/or via L1 control signaling(e.g., PDCCH order) used to initiate a two-step RA procedure.

For example, in a macro coverage area, a wireless device may have astored and/or persisted TA value, e.g., a stationary or near stationarywireless device such as a sensor-type wireless device. In this case atwo-step RA procedure may be initiated. A base station having macrocoverage may use broadcasting and/or dedicated signaling to configure atwo-step RA procedure with one or more wireless devices having storedand/or persisted TA value(s) under the coverage.

A wireless device in an RRC CONNECTED 602 state may perform a two-stepRA procedure. For example, the two-step RA procedure may be initiatedwhen a wireless device performs a handover (e.g., network-initiatedhandover), and/or when the wireless device requires or requests a ULgrant for a transmission of delay-sensitive data and there are nophysical-layer uplink control channel resources available to transmit ascheduling request. A wireless device in an RRC INACTIVE 604 state mayperform a two-step RA procedure, e.g., for a small data transmissionwhile remaining in the RRC INACTIVE 604 state or for resuming aconnection. A wireless device may initiate a two-step RA procedure, forexample, for initial access such as establishing a radio link,re-establishment of a radio link, handover, establishment of ULsynchronization, and/or a scheduling request when there is no UL grant.

The following description presents one or more examples of an RAprocedure. The procedures and/or parameters described in the followingmay not be limited to a specific type of an RA procedure. The proceduresand/or parameters described in the following may be applied for afour-step RA procedure and/or a two-step RA procedure. For example, anRA procedure may refer to a four-step RA procedure and/or a two-step RAprocedure in the following description.

A wireless device may perform a cell search. For example, the wirelessdevice may acquire time and frequency synchronization with the cell anddetect a first physical layer cell ID of the cell during the cell searchprocedure. The wireless device may perform the cell search, for example,when the wireless device has received one or more synchronizationsignals (SS), for example, the primary synchronization signal (PSS) andthe secondary synchronization signal (SSS). The wireless device mayassume that reception occasions of one or more physical broadcastchannels (PBCH), PSS, and SSS are in consecutive symbols, and, forexample, form a SS/PBCH block (SSB). For example, the wireless devicemay assume that SSS, PBCH demodulation reference signal (DM-RS), andPBCH data have the same energy per resource element (EPRE). For example,the wireless device may assume that the ratio of PSS EPRE to SSS EPRE ina SS/PBCH block is a particular value (e.g., either 0 dB or 3 dB). Forexample, the wireless device may determine that the ratio of PDCCH DM-RSEPRE to SSS EPRE is within a particular range (e.g., from −8 dB to 8dB), for example, when the wireless device has not been provideddedicated higher layer parameters e.g., semi-statically configured byRRC message(s).

A wireless device may determine a first symbol index for one or morecandidate SS/PBCH block. For example, for a half frame with SS/PBCHblocks, the first symbol index for one or more candidate SS/PBCH blocksmay be determined according to a subcarrier spacing of the SS/PBCHblocks. For example, index 0 corresponds to the first symbol of thefirst slot in a half-frame. As an example, the first symbol of the oneor more candidate SS/PBCH blocks may have indexes {2, 8}+14·n for 15 kHzsubcarrier spacing, where, for example, n=0, 1 for carrier frequenciessmaller than or equal to 3 GHz, and for example, n=0, 1, 2, 3 forcarrier frequencies larger than 3 GHz and smaller than or equal to 6GHz. The one or more candidate SS/PBCH blocks in a half frame may beindexed in an ascending order in time, for example, from 0 to L−1. Thewireless device may determine some bits (for example, the 2 leastsignificant bits (LSB) for L=4, or the 3 LSB bits for L>4) of a SS/PBCHblock index per half frame from, for example, a one-to-one mapping withone or more index of a DM-RS sequence transmitted in the PBCH.

Prior to initiation of a random access procedure, a base station maytransmit one or more RRC messages to configure a wireless device withone or more parameters of RACH configuration, e.g., for a four-step RAprocedure, a two-step RA procedure, and/or both of four-step andtwo-step RA procedures. The one or more RRC messages may broadcast ormulticast to one or more wireless devices. The one or more RRC messagesmay be wireless device-specific messages, e.g., a dedicated RRC messagestransmitted to a wireless device with RRC INACTIVE 1520 or RRC CONNECTED1530. The one or more RRC messages may comprise one or more parametersrequired for transmitting at least one preamble via one or more randomaccess resources. For example, the one or more parameters may indicateat least one of the following: PRACH resource allocation (e.g., resourceallocation of one or more PRACH occasions), preamble format, SSBinformation (e.g., total number of SSBs, downlink resource allocation ofSSB transmission, transmission power of SSB transmission, SSB indexcorresponding to a beam transmitting the one or more RRC messages and/orother information), and/or uplink radio resources for one or moretransport block transmissions.

The base station may further transmit one or more downlink referencesignals. For example, the one or more downlink reference signals maycomprise one or more discovery reference signals. The wireless devicemay select a first downlink reference signal among the one or moredownlink reference signals. For example, the first downlink referencesignal may comprise one or more synchronization signals and a physicalbroadcast channel (SS/PBCH). For example, the wireless device may adjusta downlink synchronization based on the one or more synchronizationsignals. For example, the one or more downlink reference signals maycomprise one or more channel state information-reference signals(CSI-RS).

The one or more RRC messages may further comprise one or more parametersindicating one or more downlink control channels, for example, PDDCH.Each of the one or more downlink control channels may be associated withat least one of the one or more downlink reference signals. For example,the first downlink reference signal may comprise one or more systeminformation (e.g., master information block (MIB) and/or systeminformation block (SIB)). The base station may transmit message(s)comprising the one or more system information, for example, on thephysical broadcast channel (PBCH), physical downlink control channel(PDCCH), and/or physical downlink shared channel (PDSCH).

The one or more system information may comprise at least one informationelement (e.g., PDCCH-Config, PDCCH-ConfigSIB1, PDCCH-ConfigCommon,and/or any combination thereof). The at least one information elementmay be transmitted from a base station, for example, to indicate, to awireless device, one or more control parameters. The one or more controlparameters may indicate one or more control resource sets (CORESET). Forexample, the one or more control parameters comprises the parametersindicating a first common CORESET#0 (e.g., controlResourceSetZero),and/or a second common CORESET (e.g., commonControlResourceSet). The oneor more control parameters may further comprise one or more search spacesets. For example, the one or more control parameters comprise theparameters of a first search space for the system information block(e.g., searchSpaceSIB1), and/or a first common search space#0 (e.g.,searchSpaceZero), and/or a first random access search space (e.g.,ra-SearchSpace), and/or a first paging search space (e.g.,pagingSearchSpace). The wireless device may use the one or more controlparameters to for acquiring, configuring, and/or monitoring the one ormore downlink control channels.

A wireless device may monitor a set of one or more candidates for theone or more downlink control channels in the one or more controlresource sets. The one or more control resource sets may be defined in afirst active downlink frequency band, e.g., an active bandwidth part(BWP), on a first activated serving cell. For example, the firstactivated serving cell is configured, by a network, to a wireless devicewith the one or more search space sets. For example, the wireless devicedecodes each of the one or more downlink control channels in the set ofcandidates for the one or more downlink control channels according to afirst format of a first downlink control information (DCI). The set ofcandidates for the one or more downlink control channels may be definedin terms of the one or more search space sets. For example, the one ormore search space sets are one or more common search space sets (e.g.,Type0-PDCCH, Type0A-PDCCH, Type1-PDCCH, Type2-PDCCH, and/orType3-PDCCH), one or more wireless device-specific search space sets,and/or any combination thereof.

For example, the wireless device may monitor the set of candidates forthe one or more downlink control channels in a Type0-PDCCH common searchspace set. For example, the Type0-PDCCH common search space set may beconfigured by the at least one information element, e.g., thePDCCH-ConfigSIB1 in the MIB. For example, the Type0-PDCCH common searchspace set may be configured by the one or more search space sets, e.g.,a searchSpaceSIB1 in the PDCCH-ConfigCommon, or the searchSpaceZero inthe PDCCH-ConfigCommon. For example, the Type0-PDCCH common search spaceset may be configured for a first format of a first downlink controlinformation scrambled by a particular radio network temporaryidentifier, e.g., a system information-radio network temporaryidentifier (SI-RNTI).

For example, the wireless device may monitor the set of candidates forthe one or more downlink control channels in a Type1-PDCCH common searchspace set. For example, the Type1-PDCCH common search space set may beconfigured by the one or more search space sets, e.g., thera-searchSpace in the PDCCH-ConfigCommon. For example, the Type1-PDCCHcommon search space set may be configured for a second format of asecond downlink control information scrambled by a second radio networktemporary identifier, e.g., a random access-radio network temporaryidentifier (RA-RNTI), a temporary cell-radio network temporaryidentifier (TC-RNTI), C-RNTI, and/or an RNTI that generated by awireless device based on a two-step RA procedure, e.g., MsgB-RNTI.

The wireless device may determine, for example during a cell search,that a first control resource set for a first common search space (e.g.,Type0-PDCCH) is present. The first control resource set may comprise oneor more resource blocks and one or more symbols. The one or more RRCmessages may comprise one or more parameters indicating one or moremonitoring occasions of the one or more downlink control channels. Forexample, the wireless device determines a number of consecutive resourceblocks and a number of consecutive symbols for the first controlresource set of the first common search space. For example, one or morebits (e.g., a four most significant bits) of the at least oneinformation element (e.g., PDCCH-ConfigSIB1) indicates the number ofconsecutive resource blocks and the number of consecutive symbols. Thewireless device may determine the one or more monitoring occasions ofthe one or more downlink control channels from one or more bits (e.g., afour least significant bits) of the at least one information element(e.g., PDCCH-ConfigSIB1). For example, the one or more monitoringoccasions of the one or more downlink control channels associated with afirst downlink reference signal (e.g., SSB or CSI-RS) are determinedbased on one or more system frame numbers and one or more slot indexesof the first control resource set. For example, the first downlinkreference signal with a first index overlaps in time with the firstframe number and the first slot index.

The wireless device may select (or determine) a particular downlinkchannel from the one or more downlink control channels, based on a firstdownlink reference signal (e.g., SSB or CSI-RS). For example, thewireless device receives message(s) indicating associations between theone or more downlink control channels and one or more downlink referencesignals. The wireless device may select the first downlink referencesignal (e.g., SSB or CSI-RS) from the one or more downlink referencesignals, for example, based on an RSRP of the first downlink referencesignal larger than a first value. Based on the associations, thewireless device determine the particular downlink channel associatedwith the first downlink reference signal. The wireless device maydetermine that a demodulation reference signal antenna port associatedwith a reception of the first downlink channel is quasi co-located (QCL)with the first downlink reference signal. For example, the demodulationreference signal antenna port associated with the reception of the firstdownlink channel and the first downlink reference signal (e.g., thecorresponding SS/PBCH block) may be quasi co-located with respect to atleast one of the following: an average gain, QCL-TypeA, and/orQCL-TypeD.

A wireless device may receive, from a base station, one or more RRCmessages comprising one or more random access parameters. For example,the one or more RRC messages comprise a common (or generic) randomaccess configuration message (e.g., RACH-ConfigCommon and/orRACH-ConfigGeneric) indicating at least one of: a total number of randomaccess preambles (e.g., totalNumberOfRA-Preambles), one or more PRACHconfiguration index (e.g., prach-ConfigurationIndex), a number of PRACHoccasions that may be multiplexed in frequency domain (FDMed) in a timeinstance (e.g., msg1-FDM), an offset of a lowest PRACH occasion infrequency domain with respect to a first resource block (e.g.,msg1-FrequencyStart), a power ramping step for PRACH (e.g.,powerRampingStep), a target power level at the network receiver side(preambleReceivedTargetPower), a maximum number of random accesspreamble transmission that may be performed (e.g., preambleTransMax), awindow length for a random access response (i.e., RAR, e.g., Msg2)(e.g., ra-ResponseWindow), a number of SSBs per random access channel(RACH) occasion and a number of contention-based preambles per SSB(e.g., ssb-perRACH-OccasionAndCB-PreamblesPerSSB). For example, thetotal number of random access preambles may be a multiple of the numberof SSBs per RACH occasion. For example, the window length for RAR may bein number of slots. For example, a dedicated random access configurationmessage (e.g., RACH-ConfigDedicated) may comprise one or more RACHoccasions for contention-free random access (e.g., occasions), and oneor more PRACH mask index for random access resource selection (e.g.,ra-ssb-OccasionMaskIndex).

The one or more random access parameters (e.g.,ssb-perRACH-OccasionAndCB-PreamblesPerSSB) may indicate a first number(e.g., N) of the one or more downlink reference signals (e.g., SS/PBCHblocks) that may be associated with a first PRACH occasion. The one ormore random access parameters (e.g.,ssb-perRACH-OccasionAndCB-PreamblesPerSSB) may indicate a second number(e.g., R) of the one or more random access preambles for the firstdownlink reference signal and for the first PRACH occasion. The one ormore random access preambles may be contention based preambles. Thefirst downlink reference signal may be a first SS/PBCH block. Forexample, the first number (e.g., if N<1) indicates that the firstSS/PBCH block may be mapped to at least one (e.g., 1/N) consecutivevalid PRACH occasions. For example, the second number (e.g., R)indicates that at least one preamble with consecutive indexes associatedwith the first SS/PBCH block may start from the first preamble index forthe first valid PRACH occasion.

For example, the one or more PRACH configuration indexes (e.g.,prach-ConfigurationIndex), may indicate a preamble format, a periodicityfor the one or more PRACH time resources, one or more PRACH subframenumbers, a number of PRACH slots within the one or more PRACH subframes,a PRACH starting symbol number, and/or a number of time domain PRACHoccasions within a PRACH slot.

The one or more random access parameters may further comprise anassociation period for mapping the one or more SS/PBCH blocks to the oneor more PRACH occasions. For example, the one or more SS/PBCH blockindexes are mapped to the one or more PRACH occasions based on an order.An example of the order may be as follows: in increasing order of theindexes of the at least one preamble in the first PRACH occasion; inincreasing order of the indexes of the one or more frequency resources(e.g., for frequency multiplexed PRACH occasions); in increasing orderof the indexes of the one or more time resources (e.g., for timemultiplexed PRACH occasions) in the first PRACH slot; and/or inincreasing order of the indexes for the PRACH slots.

A control order initiating an RA procedure (e.g., for SCell additionand/or TA update) may comprising at least one PRACH mask index. The atleast PRACH mask index may indicate one or more PRACH occasionsassociated with one or more downlink reference signals (e.g., SSBsand/or CSI-RS). FIG. 18 shows an example of PRACH mask index values thatmay be indicated by the control order. A wireless device may identifyone or more PRACH occasion(s) of a particular downlink reference signal(e.g., SSB and/or CSI-RS) based on a PRACH mask index value indicated bythe control order (e.g., PDCCH order). The control order (e.g., PDCCH)may comprise a field indicating a particular SSB (or CSI-RS). Forexample, the allowed PRACH occasions in FIG. 18 may be mapped (e.g.,consecutively) for an index of the particular SSB. The wireless devicemay select the first PRACH occasion indicated by a first PRACH maskindex value for the particular SSB in the first association period. Thefirst association period may be a first mapping cycle. The wirelessdevice may reset the one or more indexes of the one or more PRACHoccasions for the first mapping cycle.

A wireless device may receive, from a base station, one or more messagesindicating random access parameters of a random access procedure in FIG.13A and/or FIG. 13B) and/or a two-step random access procedure in FIG.13C. For example, the one or more messages are broadcast RRC message(s),wireless device specific RRC message(s), and/or combination thereof. Forexample, the one or more message comprise at least one of random accesscommon configuration (e.g., RACH-ConfigCommon), random access genericconfiguration (e.g., RACH-ConfigGeneric), and/or random accessconfiguration dedicated to a wireless device (e.g.,RACH-ConfigDedicated). For example, for a contention based (four-stepand/or a two-step) random access procedure, a wireless device receives,from a base station, at least RACH-ConfigCommon and RACH-ConfigGeneric.For example, for a contention free (four-step and/or a two-step) randomaccess procedure, a wireless device receives, from a base station, atleast RACH-ConfigDedicated together with RACH-ConfigCommon and/orRACH-ConfigGeneric. A random access procedure on an SCell may beinitiated by a PDCCH order with ra-PreambleIndex different from a firstindex (that may be predefined or configured e.g., 0b000000).

A wireless device may initiate a random access procedure at least basedon parameter(s) configured in at least one of RACH-ConfigCommon,RACH-ConfigGeneric, and RACH-ConfigDedicated. For example, a wirelessdevice initiates a random access procedure, for example, after or inresponse to receiving a PDCCH order from a base station, by the MACentity of the wireless device and/or by RRC of the wireless device. Awireless device may be in one or more conditions based on which one ormore random access procedure need to be initiated. For example, thereexists one random access procedure ongoing at any point in time in a MACentity. A wireless device may continue with the ongoing procedure orstart with the new procedure (e.g. for SI request), for example, if anMAC entity of a wireless device receives a request for a random accessprocedure while another is already ongoing in the MAC entity.

An example random access common configuration (e.g., RACH-ConfigCommon)may be below:

RACH-ConfigCommon ::= SEQUENCE {  rach-ConfigGeneric RACH-ConfigGeneric, totalNumberOfRA-Preambles INTEGER (1..63) OPTIONAL, ssb-perRACH-OccasionAndCB-PreamblesPerSSB CHOICE {  oneEighth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64},  oneFourth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64},  oneHalf  ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64},  one    ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64},  two    ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32},   four     INTEGER(1..16),   eight    INTEGER (1..8),   sixteen   INTEGER (1..4)  }OPTIONAL, -- Need M  groupBconfigured SEQUENCE {   ra-Msg3SizeGroupAENUMERATED { b56, b144, b208, b256, b282,  b480, b640, b800, b1000,spare7, spare6, spare5, spare4, spare3, spare2, spare1},  messagePowerOffsetGroupB ENUMERATED {minusinfinity, dBO, dB5, dB8,dB10, dB 12, dB15, dB18},   numberOfRA-PreamblesGroupA INTEGER (1..64) } OPTIONAL, -- Need R  ra-ContentionResolutionTimer ENUMERATED { sf8,sf16, sf24, sf32, sf40, sf48, sf56, sf64},  rsrp-ThresholdSSB RSRP-RangeOPTIONAL, -- Need R  rsrp-ThresholdSSB-SUL  RSRP-Range OPTIONAL, -- CondSUL  prach-RootSequenceIndex  CHOICE {   1839 INTEGER (0..837),  1139 INTEGER (0..137)  }, msg1-SubcarrierSpacing SubcarrierSpacing OPTIONAL, -- Need S restrictedSet Config ENUMERATED { unrestrictedSet, restrictedSetTypeA,restrictedSetTypeB},  msg3-transformPrecoding ENUMERATED {enabled}OPTIONAL, -- Need R, ... }

For example, messagePowerOffsetGroupB indicates a threshold for preambleselection. The value of messagePowerOffsetGroupB may be in dB. Forexample, minusinfinity in RACH-ConfigCommon corresponds to infinity. Thevalue dB0 may correspond to 0 dB, dB5 may correspond to 5 dB and so on.msg1-SubcarrierSpacing in RACH-ConfigCommon may indicate a subcarrierspacing of PRACH. One or more values, e.g., 15 or 30 kHz (<6 GHz), 60 or120 kHz (>6 GHz) may be applicable. There may be a layer 1 parameter(e.g., ‘prach-Msg1SubcarrierSpacing) corresponding tomsg1-SubcarrierSpacing. A wireless device may apply the SCS as derivedfrom the prach-ConfigurationIndex in RACH-ConfigGeneric, for example, ifthis parameter is absent. A base station may employmsg3-transformPrecoding to indicate to a wireless device whethertransform precoding is enabled for data transmission (e.g., Msg3 in afour-step RA procedure and/or one or more TB transmission in a two-stepRA procedure). Absence of msg3-transfromPrecoding may indicate that itis disabled. numberOfRA-PreamblesGroupA may indicate a number ofcontention based (CB) preambles per SSB in group A. This may determineimplicitly the number of CB preambles per SSB available in group B. Thesetting may be consistent with the setting ofssb-perRACH-OccasionAndCB-PreamblesPerSSB. prach-RootSequenceIndex mayindicate PRACH root sequence index. There may be a layer 1 parameter(e.g., ‘PRACHRootSequenceIndex’) corresponding tossb-perRACH-OccasionAndCB-PreamblePerSSB. The value range may depend ona size of preamble, e.g., whether a preamble length (L) is L=839 orL=139. ra-ContentionResolutionTimer may indicate an initial value forthe contention resolution timer. For example, a value ms8 inRACH-ConfigCommon may indicate 8 ms, value ms16 may indicate 16 ms, andso on. ra-Msg3SizeGroupA may indicate a transport blocks size thresholdin bit. For example, a wireless device may employ a contention based RApreamble of group A, for example, when the transport block size is belowra-Msg3SizeGroupA. rach-ConfigGeneric may indicate one or more genericRACH parameters in RACH-ConfigGeneric. restrictedSetConfig may indicatea configuration of an unrestricted set or one of two types of restrictedsets. rsrp-ThresholdSSB may indicate a threshold for SS block selection.For example, a wireless device may select the SS block and correspondingPRACH resource for path-loss estimation and (re)transmission based on SSblocks that satisfy the threshold. rsrp-ThresholdSSB-SUL may indicate athreshold for uplink carrier selection. For example, a wireless devicemay select a supplementary uplink (SUL) carrier to perform random accessbased on this threshold. ssb-perRACH-OccasionAndCB-PreamblesPerSSB mayindicate a number of SSBs per RACH occasion and a number of contentionbased preambles per SSB. There may be layer 1 one or more parameters(e.g., ‘SSB-per-rach-occasion’ and/or ‘CB-preambles-per-SSB’)corresponding to ssb-perRACH-OccasionAndCB-PreamblesPerSSB. For example,a total number of CB preambles in a RACH occasion may be given byCB-preambles-per-SSB*max(1,SSB-per-rach-occasion).totalNumberOfRA-Preambles may indicate a total number of preamblesemployed for contention based and contention free random access. Forexample, totalNumberOfRA-Preambles may not comprise one or morepreambles employed for other purposes (e.g. for SI request). A wirelessdevice may use one or more of 64 preambles for RA, for example, if thefield is absent.

An example random access common configuration of RACH-ConfigGeneric maybe below:

RACH-ConfigGeneric ::= SEQUENCE {  prach-ConfigurationIndex  INTEGER(0..255),  msg1-FDM         ENUMERATED {one, two, four, eight}, msg1-FrequencyStart     INTEGER (0..maxNrofPhysicalResourceBlocks-1), zeroCorrelationZoneConfig  INTEGER(0..15), preambleReceivedTargetPower INTEGER (−202 ..−60), preambleTransMax  ENUMERATED {n3, n4, n5, n6, n7,n8, n10, n20, n50,n100, n200},  powerRampingStep     ENUMERATED {dB0, dB2, dB4, dB6}, ra-Response Window     ENUMERATED {sl1, sl2, sl4, sl8, sl10, sl20,sl40, s180}, ... }

For example, msg1-FDM may indicate a number of PRACH transmissionoccasions FDMed in one time instance. There may be a layer 1 parameter(e.g., ‘prach-FDM’) corresponding to msg1-FDM. msg1-FrequencyStart mayindicate an offset of PRACH transmission occasion (e.g., lowest PRACHtransmission occasion) in frequency domain with respective to aparticular PRB (e.g., PRB 0). A base station may configure a value ofmsg1-FrequencyStart such that the corresponding RACH resource is withinthe bandwidth of the UL BWP. There may be a layer 1 parameter (e.g.,‘prach-frequency-start’) corresponding to msg1-FreqencyStart.powerRampingStep may indicate power ramping steps for PRACH.prach-ConfigurationIndex may indicate a PRACH configuration index. Forexample, a radio access technology (e.g., LTE, and/or NR) may predefineone or more PRACH configurations, and prach-ConfigurationIndex mayindicate one of the one or more PRACH configurations. There may be alayer 1 parameter (e.g., ‘PRACHConfigurationIndex’) corresponding toprach-ConfigurationIndex. preambleReceivedTargetPower may indicate atarget power level at the network receiver side. For example, multiplesof a particular value (e.g., in dBm) may be chosen. RACH-ConfigGenericabove shows an example when multiples of 2 dBm are chosen (e.g. −202,−200, −198, . . . ). preambleTransMax may indicate a number of RApreamble transmissions performed before declaring a failure. Forexample, preambleTransMax may indicate a maximum number of RA preambletransmissions performed before declaring a failure. ra-ResponseWindowmay indicate an RAR window length in number of slots (or subframes,mini-slots, and/or symbols). a base station may configure a value lowerthan or equal to a particular value (e.g., 10 ms). The value may belarger than a particular value (e.g., 10 ms). zeroCorrelationZoneConfigmay indicate an index of preamble sequence generation configuration(e.g., N-CS configuration). A radio access technology (e.g., LTE and/orNR) may predefine one or more preamble sequence generationconfigurations, and zeroCorrelationZoneConfig may indicate one of theone or more preamble sequence generation configurations. For example, awireless device may determine a cyclic shift of preamble sequence basedon zeroCorrelationZoneConfig. zeroCorrelationZoneConfig may determine aproperty of random access preambles (e.g., a zero correlation zone)

An example random access dedicated configuration (e.g.,RACH-ConfigDedicated) may be below:

RACH-ConfigDedicated ::= SEQUENCE {  cfra      CFRA       OPTIONAL, --Need N  ra-Prioritization RA-Prioritization  OPTIONAL, -- Need N  ... }CFRA ::= SEQUENCE {  occasions SEQUENCE {  rach-ConfigGeneric        RACH-ConfigGeneric,  ssb-perRACH-Occasion     ENUMERATED {oneEighth, oneFourth, oneHalf,one, two, four, eight, sixteen} OPTIONAL -- Cond SSB-CFRA  } OPTIONAL,-- Need S  resources CHOICE {   ssb   SEQUENCE {    ssb-ResourceListSEQUENCE (SIZE(1..maxRA-SSB-Resources)) OF CFRA-SSB-Resource,   ra-ssb-OccasionMaskIndex INTEGER (0..15)   },   csirs SEQUENCE {   csirs-ResourceList SEQUENCE (SIZE(1..maxRA-CSIRS-Resources)) OFCFRA-CSIRS-Resource,    rsrp-ThresholdCSI-RS RSRP-Range   }  },  ... }CFRA-SSB-Resource ::= SEQUENCE {  ssb       SSB-Index, ra-PreambleIndex INTEGER (0..63),  ... } CFRA-CSIRS-Resource::= SEQUENCE {  csi-RS         CSI-RS-Index, ra-OccasionList      SEQUENCE (SIZE(1..maxRA-OccasionsPerCSIRS)) OFINTEGER (0..maxRA-Occasions-1),  ra-PreambleIndex    INTEGER (0..63), ... }

For example, a CSI-RS is indicated, to a wireless device, by anidentifier (e.g., ID) of a CSI-RS resource defined in the measurementobject associated with this serving cell. ra-OccasionList may indicateone or more RA occasions. A wireless device may employ the one or moreRA occasions, for example, when the wireless device performs acontention-free random access (CFRA) procedure upon selecting thecandidate beam identified by the CSI-RS. ra-PreambleIndex may indicatean RA preamble index to use in the RA occasions associated with thisCSI-RS. ra-ssb-OccasionMaskIndex may indicate a PRACH Mask Index for RAResource selection. The mask may be valid for one or more SSB resourcessignaled in ssb-ResourceList. rach-ConfigGeneric may indicate aconfiguration of contention free random access occasions for the CFRAprocedure. ssb-perRACH-Occasion may indicate a number of SSBs per RACHoccasion. ra-PreambleIndex may indicate a preamble index that a wirelessdevice may employ when performing CFRA upon selecting the candidatebeams identified by this SSB. ssb in RACH-ConfigDedicated may indicatean identifier (e.g., ID) of an SSB transmitted by this serving cell.cfra in RACH-ConfigDedicated may indicate one or more parameters forcontention free random access to a given target cell. A wireless devicemay perform contention based random access, for example, if the field(e.g., cfra) is absent. ra-prioritization may indicate one or moreparameters which apply for prioritized random access procedure to agiven target cell. A field, SSB-CFRA, in RACH-ConfigDedicated may bepresent, for example, if the field resources in CFRA is set to ssb;otherwise it may be not present.

A wireless device may receive, from a base station, one or more RRCmessage indicating at least one of:

-   -   an available set of PRACH occasions for the transmission of the        Random Access Preamble (e.g., prach-ConfigIndex), an initial        Random Access Preamble power (e.g.,        preambleReceivedTargetPower), an RSRP threshold for the        selection of the SSB and corresponding Random Access Preamble        and/or PRACH occasion (e.g., rsrp-ThresholdSSB,        rsrp-ThresholdSSB may be configured in a beam failure recovery        configuration, e.g., BeamFailureRecoveryConfig IE, for example,        if the Random Access procedure is initiated for beam failure        recovery), an RSRP threshold for the selection of CSI-RS and        corresponding Random Access Preamble and/or PRACH occasion        (e.g., rsrp-ThresholdCSI-RS, rsrp-ThresholdCSI-RS may be set to        a value calculated based on rsrp-ThresholdSSB and an offset        value, e.g., by multiplying rsrp-ThresholdSSB by        powerControlOffset), an RSRP threshold for the selection between        the NUL carrier and the SUL carrier (e.g.,        rsrp-ThresholdSSB-SUL), a power offset between rsrp-ThresholdSSB        and rsrp-ThresholdCSI-RS to be employed when the Random Access        procedure is initiated for beam failure recovery (e.g.,        powerControlOffset),    -   a power-ramping factor (e.g., powerRampingStep), a power-ramping        factor in case of differentiated Random Access procedure (e.g.,        powerRampingStepHighPriority), an index of Random Access        Preamble (e.g., ra-PreambleIndex), an index (e.g.,        ra-ssb-OccasionMaskIndex) indicating PRACH occasion(s)        associated with an SSB in which the MAC entity may transmit a        Random Access Preamble (e.g., FIG. 18 shows an example of        ra-ssb-OccasionMaskIndex values), PRACH occasion(s) associated        with a CSI-RS in which the MAC entity may transmit a Random        Access Preamble (e.g., ra-OccasionList), a maximum number of        Random Access Preamble transmission (e.g., preambleTransMax), a        number of SSBs mapped to each PRACH occasion and a number of        Random Access Preambles mapped to each SSB (e.g.,        ssb-perRACH-OccasionAndCB-PreamblesPerSSB, the time window        (duration, and/or interval) to monitor RA response(s) (e.g.,        ra-ResponseWindow) and/or a Contention Resolution Timer (e.g.,        ra-ContentionResolutionTimer).

In an example, a wireless device initiates an RA procedure for beamfailure detection and recovery. For example, a wireless device receives,from a base station, RRC message(s) for a beam failure recoveryprocedure. The wireless device may indicate, to the serving base stationbased on the beam failure recovery procedure, SSB(s) or CSI-RS(s) onwhich the wireless device detects a beam failure among one or moreserving SSB(s)/CSI-RS(s). Beam failure may be detected by counting oneor more beam failure instance indication from the lower layers to theMAC entity of the wireless device. For example, a wireless devicereceive, from a base station, an RRC message (e.g., comprising a beamfailure recovery configuration, e.g., BeamFailureRecoveryConfig)indicating at least one of following: beamFailureInstanceMaxCount forthe beam failure detection. beamFailureDetectionTimer for the beamfailure detection, beamFailureRecoveryTimer for the beam failurerecovery procedure, rsrp-ThresholdSSB for an RSRP threshold for the beamfailure recovery, powerRampingStep for the beam failure recovery,preambleReceivedTargetPower, preambleReceivedTargetPower for the beamfailure recovery, preambleTransMax for the beam failure recovery, thetime window (e.g., ra-ResponseWindow) to monitor response(s) for thebeam failure recovery using contention-free Random Access Preamble,prach-ConfigIndex for the beam failure recovery,ra-ssb-OccasionMaskIndex for the beam failure recovery, ra-OccasionListfor the beam failure recovery.

A wireless device may employ (or use or maintain) one or more parameters(or variables) for a random access procedure. For example, the one ormore parameters (or variables) comprise at least one of: PREAMBLE_INDEX;PREAMBLE_TRANSMISSION_COUNTER; PREAMBLE_POWER_RAMPING_COUNTER;PREAMBLE_POWER_RAMPING_STEP; PREAMBLE_RECEIVED_TARGET_POWER;PREAMBLE_BACKOFF; PCMAX; SCALING_FACTOR_BI; and TEMPORARY_C-RNTI.

A wireless device may perform a random access resource selection forselecting one or more preambles and one or more PRACH occasion (orresources comprising time, frequency, and/or code). For example, theremay be one or more cases that a random access procedure may be initiatedfor beam failure recovery; and/or the beamFailureRecoveryTimer is eitherrunning or not configured; and/or the contention-free Random AccessResources for beam failure recovery request associated with any of theSSBs and/or CSI-RSs have been explicitly provided by RRC; and/or atleast one of the SSBs with SS-RSRP above rsrp-ThresholdSSB amongst theSSBs in candidateBeamRSList or the CSI-RSs with CSI-RSRP aboversrp-ThresholdCSI-RS amongst the CSI-RSs in candidateBeamRSList isavailable. In this case, a wireless device may select one or more SSBswith corresponding one or more SS-RSRP values above rsrp-ThresholdSSBamongst the SSBs in candidateBeamRSList or one or more CSI-RSs withcorresponding one or more CSI-RSRP values above rsrp-ThresholdCSI-RSamongst the CSI-RSs in candidateBeamRSList. For example, a wirelessdevice may select at least one CSI-RS and set the PREAMBLE_INDEX to ara-PreambleIndex corresponding to the SSB in candidateBeamRSList whichis quasi-collocated with the at least one CSI-RSselected by the wirelessdevice, for example, if there is no ra-PreambleIndex associated with theat least one CSI-RS, otherwise the wireless device may set thePREAMBLE_INDEX to a ra-PreambleIndex corresponding to the selected SSBor CSI-RS from the set of Random Access Preambles for beam failurerecovery request.

A wireless device may receive, via PDCCH or RRC, a ra-PreambleIndexwhich is not a particular preamble index (that may be predefined orconfigured e.g., 0b000000). In this case, the wireless device may setthe PREAMBLE_INDEX to the signalled ra-PreambleIndex.

There may be one or more cases that the contention-free Random AccessResources associated with SSBs have been explicitly provided, to awireless device via RRC, and at least one SSB with SS-RSRP aboversrp-ThresholdSSB amongst the associated SSBs is available. In thiscase, the wireless device may select an SSB with SS-RSRP aboversrp-ThresholdSSB amongst the associated SSBs. For example, the wirelessdevice sets the PREAMBLE_INDEX to a ra-PreambleIndex corresponding tothe selected SSB.

There may be one or more cases that the contention-free random accessresources associated with CSI-RSs have been explicitly provided, to awireless device via RRC, and at least one CSI-RS with CSI-RS RSRP aboversrp-ThresholdCSI-RS amongst the associated CSI-RSs is available. Inthis case, a wireless device may select a CSI-RS with CSI-RSRP aboversrp-ThresholdCSI-RS amongst the associated CSI-RSs. For example, thewireless device sets the PREAMBLE_INDEX to a ra-PreambleIndexcorresponding to the selected CSI-RS.

There may be one or more cases that at least one of the SSBs withSS-RSRP above rsrp-ThresholdSSB is available. In this case, for example,a wireless device may select an SSB with SS-RSRP aboversrp-ThresholdSSB. The wireless device may select any SSB, e.g., if noneof the SSBs with SS-RSRP above rsrp-ThresholdSSB is available. Forexample, a random access resource selection is performed, e.g., when aretransmission of Msg1 1311, Msg3 1313, MsgA 1331, and/or Transportblock 1342. The wireless device may select the same group of RandomAccess Preambles as was employed for the Random Access Preambletransmission attempt corresponding to the first transmission of the Msg11311, the Msg3 1313, the MsgA 1331, and/or the Transport block 1342. Forexample, a wireless device selects a ra-PreambleIndex randomly withequal probability from the Random Access Preambles associated with theselected SSB and the selected Random Access Preambles group, e.g., ifthe association between random access preambles and SSBs is configured.For example, a wireless device selects a ra-PreambleIndex randomly withequal probability from the Random Access Preambles within the selectedRandom Access Preambles group, e.g., if the association between randomaccess preambles and SSBs is not configured. The wireless device may setthe PREAMBLE_INDEX to the selected ra-PreambleIndex.

In an example, if an SSB is selected above and an association betweenPRACH occasions and SSBs is configured, a wireless device determines thenext available PRACH occasion from the PRACH occasions corresponding tothe selected SSB permitted by the restrictions given by thera-ssb-OccasionMaskIndex if configured (e.g., the MAC entity of thewireless device may select a PRACH occasion (e.g., randomly with equalprobability) amongst the PRACH occasions occurring simultaneously but ondifferent subcarriers, corresponding to the selected SSB; the MAC entitymay take into account the possible occurrence of measurement gaps whendetermining the next available PRACH occasion corresponding to theselected SSB).

In an example, if a CSI-RS is selected above and an association betweenPRACH occasions and CSI-RSs is configured. a wireless device determinesthe next available PRACH occasion from the PRACH occasions inra-OccasionList corresponding to the selected CSI-RS (e.g. the MACentity of the wireless device may select a PRACH occasion randomly withequal probability amongst the PRACH occasions occurring simultaneouslybut on different subcarriers, corresponding to the selected CSI-RS; theMAC entity may take into account the possible occurrence of measurementgaps when determining the next available PRACH occasion corresponding tothe selected CSI-RS).

If a CSI-RS is selected above and there is no contention-free RandomAccess Resource associated with the selected CSI-RS, a wireless devicemay determine the next available PRACH occasion from the PRACHoccasions, for example, indicated by the ra-ssb-OccasionMaskIndex ifconfigured (e.g., ra-ssb-OccasionMaskIndex may indicate the restrictionspermitting which PRACH occasions available), corresponding to the SSB incandidateBeamRSList which is quasi-collocated with the selected CSI-RS(e.g., the MAC entity of the wireless device may take into account thepossible occurrence of measurement gaps when determining the nextavailable PRACH occasion corresponding to the SSB which isquasi-collocated with the selected CSI-RS).

A wireless device may determine the next available PRACH occasion. Forexample, an MAC entity of the wireless device selects a PRACH occasion(e.g., randomly with equal probability) amongst the PRACH occasionsoccurring simultaneously but on different subcarriers. The MAC entitymay determine the next available PRACH occasion based on (e.g., bytaking into account) the possible occurrence of measurement gaps.

A wireless device may perform the random access preamble transmissionbased on a selected PREABLE INDEX and PRACH occasion. For example, ifthe notification of suspending power ramping counter has not beenreceived from lower layers (e.g., physical layer); and/or if an SSBand/or a CSI-RSselected is not changed (e.g., same as the previousRandom Access Preamble transmission), a wireless device may incrementPREAMBLE_POWER_RAMPING_COUNTER, e.g., by one or to the next value (e.g.,counter step size may be predefined and/or semi-statically configured).For example, the wireless device selects a value of DELTA_PREAMBLE thatmay be predefined and/or semi-statically configured by a base stationand set PREAMBLE_RECEIVED_TARGET_POWER topreambleReceivedTargetPower+DELTA_PREAMBLE+(PREAMBLE_POWER_RAMPING_COUNTER−1)×PREAMBLE_POWER_RAMPING_STEP.

An MAC entity of the wireless device may instruct the physical layer totransmit the Random Access Preamble using the selected PRACH,corresponding RA-RNTI (e.g., if available), PREAMBLE_INDEX andPREAMBLE_RECEIVED_TARGET_POWER. For example, the wireless devicedetermines an RA-RNTI associated with the PRACH occasion in which theRandom Access Preamble is transmitted. In an example, the RA-RNTI may bedetermined in terms of index of the first OFDM symbol of the specifiedPRACH, an index of the first slot of the specified PRACH in a systemframe, an index of the specified PRACH in the frequency domain, and/oruplink carrier indicator. For example, the specified PRACH is a PRACH inwhich the wireless device transmits the Random Access Preamble. Anexample RA-RNTI is determined as:

RA-RNTI=1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id,

where s_id may be the index of the first OFDM symbol of the specifiedPRACH (0≤s_id≤14), t_id may be the index of the first slot of thespecified PRACH in a system frame (0≤t_id≤80), f_id may be the index ofthe specified PRACH in the frequency domain (0≤f_id≤8), andul_carrier_id (0 for NUL carrier, and 1 for SUL carrier or vice versa)may be the UL carrier used for Msg1 1311 transmission or Preamble 1341.In an unlicensed band, RA-RNTI may be determined further based on a SFNand/or RAR window size. For example, the RA-RNTI may be determinedfurther based on a remainder after division of the SFN by the RAR windowsize (e.g., the SFN modulo the RAR window size). An example RA-RNTIdetermination in an unlicensed band may be

RA-RNTI=1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id×14×80×8×2×(SFNmodulo RAR window size),

where the SFN is a system frame number of the first slot and RAR windowsize is configured by a higher layer parameter, e.g., ra-ResponseWindowin RACH-ConfigGeneric. For example, depending on implementation, (SFNmodulo RAR window size) may be located before any of components, s_id,14×t_id, 14×80×f_id, and/or 14×80×8×ul_carrier_id in the RA-RNTIcalculation formula.

A wireless device, that transmitted a random access preamble, may startto monitor a downlink control channel for a random access responsecorresponding to the random access preamble. For a two-step RAprocedure, the wireless device may start to monitor the downlink controlchannel, e.g., after or in response to transmitting an RAP via PRACH orafter or in response to transmitting one or more TBs via PUSCH. Thepossible occurrence of a measurement gap may not determine when awireless device starts to monitor a downlink control channel.

A wireless device may start a random access window (e.g.,ra-ResponseWindow) configured in a beam management configurationparameters (e.g., BeamFailureRecoveryConfig) at a first downlink controlchannel (e.g., PDCCH) occasion from the end of the Random AccessPreamble transmission (e.g., Msg1 1311 or Msg1 1321 for a case offour-step RA procedure) or from the end of transmission of one or moreTBs (e.g., Transport block 1342 for a case of two-step RA procedure),e.g., if the wireless device performs a contention-free random accessprocedure for a beam failure recovery request. The wireless device maymonitor the first downlink control channel of the SpCell for a responseto beam failure recovery request identified by a particular RNTI (e.g.,RA-RNTI or C-RNTI) while the random access window is running.

A wireless device may start a random access window (e.g.,ra-ResponseWindow) configured in a random access configuration parameter(e.g., RACH-ConfigCommon) at a first downlink control channel occasionfrom an end of a random access preamble transmission (e.g., Msg1 1311 orMsg1 1321 for a case of four-step RA procedure) or from an end of one ormore TBs transmission (e.g., Transport block 1342 for a case of two-stepRA procedure), e.g., if a wireless device does not perform acontention-free random access procedure for beam a failure recoveryrequest. The wireless device may monitor the first downlink controlchannel occasion of the SpCell for random access response(s) identifiedby a particular RNTI (e.g., RA-RNTI or C-RNTI) while a random accessresponse window (e.g., ra-ResponseWindow) is running.

A wireless device may receive a PDCCH based on the RA-RNTI. The PDCCHmay indicate a downlink assignment based on which the wireless devicemay receive one or more TBs comprising an MAC PDU. For example, the MACPDU comprises at least one MAC subPDU with a corresponding subheadercomprising a Random Access Preamble identifier (e.g., RAPID) matched toa preamble that a wireless device transmits to a base station. In thiscase, the wireless device may determine that a random access responsereception is successful. For example, the at least one MAC subPDUcomprises a Random Access Preamble identifier (e.g., RAPID) only, e.g.,for a random access procedure that a wireless device initiates for asystem information request.

In an RA procedure, a wireless device may receive from a base station atleast one RAR (e.g., Msg2 1312, Msg2 1322, or MsgB 1332) as a responseof Msg1 1313, Msg1 1321, or MsgA 1331. The wireless device may monitor asearch space set (e.g., the Type1-PDCCH common search space) for a firstdownlink control information (e.g., DCI format 1_0). The first downlinkcontrol information may be scrambled by a particular radio networktemporary identifier (e.g., RA-RNTI, C-RNTI, or msgB-RNTI). The firstdownlink control information may comprise a downlink assignmentindicating scheduling of PDSCH comprising the at least one RAR. Thewireless device may use the downlink assignment to identify parametersrequired for decoding/detecting the PDSCH. For example, the downlinkassignment indicates at least one of following: time and frequencyresource allocation of the PDSCH, a size of the PDSCH, MCS, etc. Thewireless device may receive the PDSCH comprising the at least one RARbased on the parameters.

A wireless device may monitor for the first downlink control information(e.g., DCI format 1_0) during a time window. The time window may beindicated by the one or more RRC messages. For example, the time windowstarts at a particular symbol (e.g., a first or a last symbol) of afirst control resource set. The wireless device may receive, from anetwork or base station, one or more RRC messages comprising one or moreparameters required for receiving the first downlink control informationon the first control resource set. The wireless device may determine alength of the time window based on the one or more parameters (e.g.,ra-ResponseWindow). The length of the time window may be defined interms of a number of slots, OFDM symbols, and/or any combinationthereof. In this case, the length may depends on a duration of slotand/or OFDM symbol that may be determined based on a numerology. Thelength of the time window may be defined based on an absolute timeduration, e.g., in terms of millisecond(s).

The wireless device may stop the time window, e.g., after or in responseto a reception of the one or more random access responses beingdetermined as successful. A reception of the one or more random accessresponses may be determined as successful, for example, when the one ormore random access responses comprise a preamble index (e.g., a randomaccess preamble identity: RAPID) corresponding to a preamble that thewireless device transmits to a base station. For example, the RAPID maybe associated with the PRACH transmission. The one or more random accessresponses may comprise an uplink grant indicating one or more uplinkresources granted for the wireless device. The wireless device maytransmit one or more transport blocks (e.g., Msg 3 1313) via the one ormore uplink resources.

An RAR may be in a form of MAC PDU comprising one or more MAC subPDUsand/or optionally padding. FIG. 19A is an example of an RAR. A MACsubheader may be octet aligned. Each MAC subPDU may comprise at leastone of following: a MAC subheader with Backoff Indicator only; a MACsubheader with RAPID only (i.e. acknowledgment for SI request); a MACsubheader with RAPID and MAC RAR. FIG. 19B is an example of a MACsubheader with backoff indicator. For example, a MAC subheader withbackoff indicator comprise one or more header fields, e.g., E/T/R/R/BIas described in FIG. 19B. A MAC subPDU with backoff indicator may beplaced at the beginning of the MAC PDU, for example, if the MAC subPDUcomprises the backoff indicator. MAC subPDU(s) with RAPID only and MACsubPDU(s) with RAPID and MAC RAR may be placed anywhere after MAC subPDUwith Backoff Indicator and, if exist before padding as described in FIG.19A. A MAC subheader with RAPID may comprise one or more header fields,e.g., E/T/RAPID as described in FIG. 19C. Padding may be placed at theend of the MAC PDU if present. Presence and length of padding may beimplicit based on TB size, size of MAC subPDU(s).

In an example, one or more header fields in a MAC subheader may indicateas follow: an E field may indicate an extension field that may be a flagindicating if the MAC subPDU including this MAC subheader is the lastMAC subPDU or not in the MAC PDU. The E field may be set to “1” toindicate at least another MAC subPDU follows. The E field may be set to“0” to indicate that the MAC subPDU including this MAC subheader is thelast MAC subPDU in the MAC PDU; a T filed may be a flag indicatingwhether the MAC subheader contains a Random Access Preamble ID or aBackoff Indicator (one or more backoff values may predefined and BI mayindicate one of backoff value). The T field may be set to “0” toindicate the presence of a Backoff Indicator field in the subheader(BI). The T field may be set to “1” to indicate the presence of a RandomAccess Preamble ID field in the subheader (RAPID); an R filed mayindicate a reserved bit that may be set to “0”; a BI field may be abackoff indicator field that identifies the overload condition in thecell. The size of the BI field may be 4 bits; an RAPID field may be aRandom Access Preamble IDentifier field that may identify thetransmitted Random Access Preamble. The MAC subPDU may not comprise aMAC RAR, for example, if the RAPID in the MAC subheader of a MAC subPDUcorresponds to one of the Random Access Preambles configured for SIrequest.

There may be one or more MAC RAR format. At least one of following MACRAR format may be employed in a four-step or a two-step RA procedure.For example, FIG. 20 is an example of one of MAC RAR formats. The MACRAR may be fixed size as depicted in FIG. 20 and may comprise at leastone of the following fields: an R field that may indicate a Reservedbit, set to “0” or “1”; a Timing Advance Command field that may indicatethe index value TA employed to control the amount of timing adjustment;a UL Grant field that indicate the resources to be employed on theuplink; and an RNTI field (e.g., Temporary C-RNTI and/or C-RNTI) thatmay indicate an identity that is employed during Random Access. Forexample, for a two-step RA procedure, an RAR may comprise at least oneof following: a UE contention resolution identity, an RV ID forretransmission of one or more TBs, decoding success or failure indicatorof one or more TB transmission, and one or more fields shown in FIG. 20.

There may be a case that a base station may multiplex, in a MAC PDU,RARs for two-step and four-step RA procedures. A wireless device may notrequire an RAR length indicator field and/or the wireless device maydetermine the boundary of each RAR in the MAC PDU based onpre-determined RAR size information, e.g., if RARs for two-step andfour-step RA procedure have the same size. For example, FIG. 21 is anexample RAR format that may be employed in a MAC PDU multiplexing an RARfor two-step and an RAR four-step RA procedures. The RAR shown in FIG.21 may be a fixed size using the same format for two-step and four-stepRA procedures. A wireless device may use (parse, interpret, ordetermine) a bit string (e.g., 6 octets) of the field for UE contentionresolution identity in FIG. 21 differently depending on a type of RAprocedure. For example, a wireless device initiating a two-step RAprocedure identifies whether a contention resolution is successful(e.g., is resolved or made) or not based on the bit string, e.g., bycomparing a contention resolution identifier with the bit string (e.g.,6 octets) of the field for UE contention resolution identity. Forexample, a wireless device initiating a four-step RA procedure uses(parses, interprets, or determines) a bit string (e.g., 6 octets)differently, e.g., other than a contention resolution purpose. Forexample, in this case, the bit string may indicate another UL grant foradditional one or more Msg3 1313 transmission opportunities, paddingbits, etc.

In an example, an RAR for a two-step RA procedure may have formats,sizes, and/or fields different from an RAR for a four-step RA procedure.For example, FIG. 22A, and FIG. 22B are example RAR formats that may beemployed for a two-step RA procedure. An RAR may comprise a field (e.g.,a reserved “R” field as shown in FIG. 21 , FIG. 22A, and FIG. 22B)indicating a type of RAR or a length of RAR, e.g., if one or more RARare (e.g., RARs for two-step and four-step RA procedures) aremultiplexed into a MAC PDU, and the RARs have different formats betweenmultiplexed RARs (e.g., between two-step RA procedure and/or betweentwo-step and four-step RA procedure). A field for indicating an RAR type(or length) may be in a subheader (such as a MAC subheader), in an MACRAR, or in a separate MAC subPDU in the RAR (e.g., like MAC subPDU 1and/or MAC subPDU 2 in FIG. 19A, there may be another MAC subPDUindicating the RAR type (or length)). An RAR may comprise differenttypes of fields that may correspond with an implicit and/or explicitindicator in a subheader or in an RAR. A wireless device may determinethe boundary of one or more RARs in a MAC PDU based on one or moreindicators.

There may be a random access response window where a wireless device maymonitor a downlink control channel for a random access responsetransmitted from a base station as a response to a preamble receivedfrom the wireless device. For example, a base station may transmit amessage comprising a value of an RAR window. For example, a cell-commonor wireless device specific random access configuration parameters(e.g., RACH-ConfigGeneric, RACH-ConfigCommon, RACH-ConfigDedicated, orServingCellConfig) in the message indicates a value of an RAR window(e.g., ra-ResponseWindow). For example, the value of an RAR window isfixed, for example, to 10 ms or other time value. For example, the valueof an RAR window is defined in terms of a number of slots as shown inRACH-ConfigGeneric. A wireless device may identify (or determine) a size(e.g., absolute time duration, and/or length) of an RAR window based ona numerology configured for a random access procedure. For example, anumerology defines one or more system parameters such as subcarrierspacing, slot duration, cyclic prefix size, number of OFDM symbol perslot, number of slots per frame, number of slots per subframe, minimumnumber of physical resource blocks, and/or maximum number of physicalresource blocks. For example, the one or more system parametersassociated with a numerology may be predefined with different subcarrierspacing, slot duration, and/or cyclic prefix size. For example, awireless device may identify a subcarrier spacing 15 kHz, normal cyclicprefix, 14 symbols per slot, 10 slots per frame, and/or 1 slot persubframe for the numerologies μ=0. For example, a wireless device mayidentify a subcarrier spacing 30 kHz, normal cyclic prefix, 14 symbolsper slot, 20 slots per frame, and/or 2 slot per subframe for thenumerologies μ=1. For example, a wireless device may identify asubcarrier spacing 60 kHz, 14 symbols per slot, 40 slots per frame,and/or 4 slot per subframe for the numerologies μ=2 with normal cyclicprefix. For example, a wireless device may identify a subcarrier spacing60 kHz, 12 symbols per slot, 40 slots per frame, and/or 4 slot persubframe for the numerologies μ=2 with extended cyclic prefix. Forexample, a wireless device may identify a subcarrier spacing 120 kHz,normal cyclic prefix, 14 symbols per slot, 80 slots per frame, and/or 8slot per subframe for the numerologies μ=3. For example, a wirelessdevice may identify a subcarrier spacing 240 kHz, normal cyclic prefix,14 symbols per slot, 160 slots per frame, and/or 16 slot per subframefor the numerologies μ=4.

A wireless device may determine (or identify) a size (e.g., duration orlength) of the RAR window based on a configured RAR window value and anumerology. For example, the RAR window has a duration of 20 ms, e.g.,if the configured RAR window value is sl20 (e.g., 20 slots) and thenumerology is μ=0 (e.g., slot duration for μ=0 is 1 ms). In an example,a particular RAR window value (e.g., ra-ResponseWindow) configured by anRRC message (e.g., broadcast and/or wireless specific unicast) may beassociated with a particular numerology. For example, inRACH-ConfigGeneric, sl10, sl20, sl40, and sl80 may be values ofra-ResponseWindow for numerologies μ=0, μ=1, μ=2, and μ=3, respectively.In an example, a base station configures a wireless device a particularRAR window value independent of a numerology. In an licensed band, asize (e.g., duration or length) of an RAR window may not be longer than10 ms (and/or a periodicity of PRACH occasion). In an unlicensed band, aduration (e.g., size or length) of an RAR window may be longer than 10ms (and/or a periodicity of PRACH occasion).

A wireless device may perform one or more retransmission of one or morepreambles during a random access procedure (e.g., two-step RA procedureand/or four-step RA procedure). There may be one or more conditions atleast based on which the wireless device determines the one or moreretransmission of one or more preambles. The wireless device maydetermine the one or more retransmission of one or more preambles, e.g.,when the wireless device determines that a random access responsereception is not successful. The wireless device may determine that arandom access response reception is not successful, e.g., if at leastone random access response comprising one or more random access preambleidentifiers that matches the transmitted PREAMBLE_INDEX has not beenreceived until an RAR window (e.g., ra-ResponseWindow configured by RRCsuch as RACH-ConfigCommon IE) expires. The wireless device may determinethat a random access response reception is not successful, for example,if a PDCCH addressed to the C-RNTI has not been received on the ServingCell where the preamble was transmitted until a RAR window for a beamfailure recovery procedure (e.g., ra-ResponseWindow configured inBeamFailureRecoveryConfig) expires.

A wireless device may determine the one or more retransmission of one ormore preambles, e.g., when the wireless device determines that acontention resolution is not successful. For example, the wirelessdevice may determine, based on Msg 3 1313 for four-step RA procedureand/or MsgB 1332 for two-step RA procedure, whether the contentionresolution is successful or not.

For example, a MAC entity of the wireless device may start a contentionresolution timer (e.g., ra-ContentionResolutionTimer) and may restartthe contention resolution timer (e.g., ra-ContentionResolutionTimer) ateach HARQ retransmission in a reference symbol (e.g., the first symbolafter the end of a Msg3 transmission), for example, once a wirelessdevice transmits, to a base station, Msg3 1313. A wireless device maydetermine that a contention resolution is not successful, for example,if the wireless device does not receive an indication of a contentionresolution while a contention resolution timer (e.g.,ra-ContentionResolutionTimer) is running. For example, the wirelessdevice may determine that a contention resolution is not successful, forexample, if the indication of the contention resolution has not beenreceived until the contention resolution timer (e.g.,ra-ContentionResolutionTimer) expires. The wireless device may discard aTEMPRARY_C-RNTI indicated by an Msg2 1312 (or Msg B 1332) after or inresponse to an expiry of the contention resolution timer (and/or inresponse to a determination of the contention resolution beingunsuccessful). If the wireless device determines that the contentionresolution is successful during the contention resolution timer (e.g.,ra-ContentionResolutionTimer) is running, the wireless device may stopthe contention resolution timer (e.g., ra-ContentionResolutionTimer).The wireless device may determine, based on a PDCCH addressed to aC-RNTI (transmitted via Msg1 1211 or MsgA 1331) detected during thecontention resolution timer is running, that the contention resolutionis successful. The wireless device may determine, based on receiving acontention resolution identifier matched to a wireless device identifier(transmitted via Msg3 1213 or MsgA 1331) detected during the contentionresolution timer is running, that the contention resolution issuccessful.

For a two-step RA procedure, a wireless device may start a timer (e.g.,RAR window, MsgB window, or contention resolution timer), e.g., after orin response to transmitting Transport block 1342 comprising a contentionresolution identifier of the wireless device. The wireless device maydetermine that the one or more retransmission of MsgA 1331 (e.g.,Preambles 1341 and/or Transport block 1342), e.g., if at least one Msg Bcomprising the contention resolution identifier that the wireless devicetransmit has not been received until the timer expires. For example, fortwo-step RA procedure, a wireless device may fallback to four-step RAprocedure based on an explicit and/or implicit indication of MsgB. Forexample, if MsgB received by the wireless device comprises such explicitindication and/or an RNTI used for detecting a PDCCH scheduling the MsgBis a particular RNTI (e.g., RA-RNTI or msgB RNTI), the wireless devicemay determine to fallback to the four-step RA procedure. The wirelessdevice may transmit Msg3, e.g., after or in response to determining thefallback to the four-step RA procedure via resource(s) indicated by ULgrant in Msg B. In this case the wireless device may follow thefour-step RA procedure, e.g., starting the contention resolution timer,and/or determining whether the contention resolution is successful ornot. The wireless device may monitor a PDCCH while the contentionresolution timer (e.g., ra-ContentionResolutionTimer) is running. Thewireless device may restart the contention resolution timer (e.g.,ra-ContentionResolutionTimer) at each HARQ retransmission in the firstsymbol after the end of a Msg3 transmission. For example, the wirelessdevice may determine that a contention resolution is not successful, forexample, if the indication of the contention resolution has not beenreceived until the contention resolution timer (e.g.,ra-ContentionResolutionTimer) expires. The wireless device may discard aTEMPRARY_C-RNTI indicated by an Msg2 1312 (or Msg B 1332) after or inresponse to an expiry of the contention resolution timer (and/or inresponse to a determination of the contention resolution beingunsuccessful). The wireless device that determines the retransmissionduring a four-step RA procedure falling back from a two-step RAprocedure may perform a retransmission of MsgA 1331. The wireless devicethat determines the retransmission during a four-step RA procedurefalling back from a two-step RA procedure may perform a retransmissionof Msg1 1311. A wireless device may stop the contention resolution timerand determine that a contention resolution is successful, for example,if a notification of a reception of a PDCCH transmission of a cell(e.g., SpCell) is received from lower layers, and the wireless deviceidentifies that the PDCCH transmission is an indication of a contentionresolution corresponding to a Msg3 transmission (or MsgB transmission)that the wireless device performed.

A wireless device may maintain (e.g., increment) a counter counting anumber of preamble transmissions (e.g., PREAMBLE_TRANSMISSION_COUNTER)by a value of counter step (e.g., by 1), for example, after or inresponse to a random access response reception being unsuccessful and/orafter or in response to a contention resolution being unsuccessful. Thewireless device may determine that a random access procedure isunsuccessfully completed and/or a MAC entity of the wireless device mayindicate a random access problem to upper layer(s), for example, if thenumber of preamble transmissions may reach a predefined orsemi-statically configured value, (e.g., ifPREAMBLE_TRANSMISSION_COUNTER=preambleTransMax+1 where preambleTransMaxis the predefined or semi-statically configured value). The wirelessdevice may determine that a random access procedure is not completedand/or one or more retransmission of one or more Msg1 1311, Msg1 1321,or MsgA 1331 may be performed, for example, if the number of preambletransmissions does not reach the predefined or semi-staticallyconfigured value, (e.g., ifPREAMBLE_TRANSMISSION_COUNTER<preambleTransMax+1).

A wireless device may delay a particular period of time (e.g., a backofftime) for performing a retransmission of one or more Msg1 1311, Msg11321, or MsgA 1331. For example, the wireless device may set the backofftime to 0 ms, for example, when a random access procedure is initiated.The wireless device may set (or update) the backoff time based on thePREAMBLE_BACKOFF determined by a value in a BI field of the MAC subPDU(e.g., BI field in FIG. 19B). A value (or a bit string) in a BI fieldmay indicate a particular backoff time in a predefined orsemi-statically configured table. For example, the wireless device mayset the PREAMBLE_BACKOFF to a value indicated by the BI field of the MACsubPDU using the predefined or semi-statically configured table. Forexample, if the wireless device receives BI indicating index 3 (or 0010in a bit string), the wireless device may set the PREAMBLE_BACKOFF to avalue of row index 3 in the predefined or semi-statically configuredtable. For example, in FIG. 19B, the example format shows that four bitsare allocated for the BI fields. In this case, there may be 16 values(e.g., each of 16 values is identified by a particular row index) in thepredefined or semi-statically configured table. The wireless device mayset the PREAMBLE_BACKOFF to a value indicated by the BI field of the MACsubPDU multiplied with a scaling factor, (e.g., SCALING_FACTOR_BI), forexample, if the wireless device receives, from a base station, one ormore RRC messages indicating the scaling factor. The wireless device mayset (or update) the PREMABLE_BACKOFF based on a BI field, for example,if a downlink assignment has been received on the PDCCH for the RA-RNTIand the received TB is successfully decoded, and/or if the Random AccessResponse comprises a MAC subPDU with Backoff Indicator (BI in FIG. 19B).The wireless device may set the PREAMBLE_BACKOFF to 0 ms, for example,if a downlink assignment has not been received on the PDCCH for theRA-RNTI and/or the received TB is not successfully decoded, and/or ifthe Random Access Response does not comprise a MAC subPDU with BackoffIndicator (BI in FIG. 20B).

A wireless device may determine the backoff time, for example, if thewireless device determines that a random access response is notsuccessful and/or a contention resolution is not successful. Thewireless device may employ a particular selection mechanism to determinethe backoff time. For example, the wireless device may determine thebackoff time based on a uniform distribution between 0 and thePREAMBLE_BACKOFF. The wireless device may employ any type ofdistribution to select the backoff time based on the PREAMBLE_BACKOFF.The wireless device may ignore the PREAMBLE_BACKOFF (e.g., a value in BIfield in FIG. 20B) and/or may not have a backoff time. For example, thewireless device may determine whether to apply the backoff time to aretransmission of at least one preamble based on an event typeinitiating the random access procedure (e.g., Beam Failure Recoveryrequest, handover, etc.) and/or a type of the random access procedure(e.g., four-step or two-step RA and/or CBRA or CFRA). For example, thewireless device may apply the backoff time to the retransmission, forexample, if the random access procedure is CBRA (e.g., where a preambleis selected by a MAC entity of the wireless device) and/or if thewireless device determines that a random access procedure is notcompleted based on a random access response reception beingunsuccessful. For example, the wireless device may apply the backofftime to the retransmission, for example, if the wireless devicedetermines that a random access procedure is not completed based on acontention resolution being unsuccessful.

A wireless device may perform a random access resource selectionprocedure (e.g., select at least one SSB or CSI-RS and/or select PRACHcorresponding to at least one SSB or CSI-RSselected by the wirelessdevice), for example, if the random access procedure is not completed.The wireless device may delay the subsequent random access preambletransmission (e.g., or delay to perform a random access resourceselection procedure) by the backoff time.

A radio access technology may allow a wireless device to change (switch)a channel (a uplink carrier, BWP, and/or a subband) to transmit at leastone preamble for a retransmission. This may increase a number ofpreamble transmission opportunities in an unlicensed band. For example,a base station may transmit, to a wireless device, one or more messages(broadcast messages, and/or RRC messages) indicating a configuration ofthe one or more channels (e.g., uplink carrier, BWPs and/or subbands)that one or more PRACH are configured. A wireless device may select oneof the one or more channels (e.g., BWPs, and/or subbands) as a channel(e.g., a uplink carrier, BWP, and/or a subband) to transmit at least onefirst preamble. The wireless device may select the channel (e.g., uplinkcarrier, BWP, and/or subband) based on an LBT result. For example, thewireless device performs one or more LBTs on one or more channels, andselect the channel among the channel(s) being sensed as idle. Thewireless device may select the one of channels being sensed as idlebased on, for example, a random selection. There may be a case thatswitching a channel for a retransmission is not allowed (e.g., thisindication may be predefined or semi-statically informed).

A wireless device may determine the transmit power of the retransmissionof at least one preamble (or MsgA) based PREAMBLE_POWER_RAMPING_COUNTER.For example, the wireless device may set PREAMBLE_POWER_RAMPING_COUNTERto an initial value (e.g., 1) as an random access procedureinitialization. The MAC entity of the wireless device may, e.g., foreach Random Access Preamble and/or for each transmission of at least onepreamble transmitted, for example, after or in response to determining arandom access reception being unsuccessful and/or a contentionresolution being unsuccessful, increment PREAMBLE_POWER_RAMPING_COUNTERby a value of a counter step predefined or semi-statically configured bya base station. For example, The MAC entity of the wireless device mayincrement PREAMBLE_POWER_RAMPING_COUNTER by 1, e.g., ifPREAMBLE_TRANSMISSION_COUNTER is greater than one; if the notificationof suspending power ramping counter has not been received from lowerlayers (e.g., the notification is received in response to a preambletransmissions being dropped due to LBT failure and/or in response to aspatial filter is changed); and/or if SSB or CSI-RSselected is notchanged from the selection in the last Random Access Preambletransmission. The wireless device may determine a value ofDELTA_PREAMBLE based on a preamble format and/or numerology selected forthe random access procedure (e.g., one or more values of DELTA_PREAMBLEare predefined associated with one or more preamble format and/ornumerology. For a given preamble format and a numerology, the wirelessdevice may select a particular value of DELTA_PREAMBLE from the one ormore values.). The wireless device may determinePREAMBLE_RECEIVED_TARGET_POWER topreambleReceivedTargetPower+DELTA_PREAMBLE+(PREAMBLE_POWER_RAMPING_COUNTER−1)×PREAMBLE_POWER_RAMPING_STEP.The MAC layer of the wireless device may instruct the physical layer totransmit the Random Access Preamble based on a selected PRACH occasion,corresponding RA-RNTI (e.g., if available), PREAMBLE_INDEX and/orPREAMBLE_RECEIVED_TARGET_POWER.

For a two-step RA procedure, MsgA (or Transport Block) may comprise acommon control channel (CCCH) SDU. For example, a transmission of theTransport Block is made for the CCCH logical channel. For example, thewireless device may transmit, to a base station via the CCCH, an RRC(re)establishment request, an RRC setup request, and/or an RRC resumerequest. The wireless device may start monitor a downlink controlchannel (e.g., a PDCCH) with the first RNTI (e.g., msgB RNTI). Thereceived PDCCH via the downlink control channel indicates a downlinkassignment of a PDSCH (e.g., MAC PDU) comprising MsgB. In this case, theMsgB (or the PDSCH (e.g., MAC PDU) comprising the MsgB) that thewireless device receives based on the downlink assignment may comprisesignalling radio bearer(s) (SRB(s)) RRC message(s). The SRB RRC messagemay comprise RRC (re)establishment, an RRC setup, and/or an RRC resumeas responses of the RRC (re)establishment request, an RRC setup request,and/or an RRC resume request, respectively, that the wireless devicetransmits via MsgA (or Transport Block).

For the case that MsgA (or Transport Block) comprises a common controlchannel (CCCH) SDU, an MAC PDU (or a PDSCH) may multiplex one or moreMsgBs for one or more wireless devices. The MAC PDU may multiplex one ormore MsgBs indicating a success of MsgA only. The MAC PDU may multiplexone or more MsgBs indicating a failure (e.g., fallback response) of MsgAonly. The MAC PDU may multiplex a plurality of MsgBs comprising one ormore responses indicating a success of MsgA and/or one or more responsesindicating a failure of MsgA (e.g., fallback RAR). The MAC PDU maycomprise at least one Backoff Indication. For a MsgB indicating asuccess of MsgA, the MsgB may comprise at least one of following: acontention resolution identifier (that is matched to an identifier thatthe wireless device transmit via MsgA), a C-RNTI, and/or a TA command.For a MsgB indicating a failure of MsgA (e.g., fallback RAR), the MsgBmay comprise at least one of following: an RAPID, a UL grant (e.g., toretransmit the MsgA payload), a TC-RNTI, and/or TA command. For example,upon receiving the MsgB indicating a failure of MsgA (e.g., fallbackRAR), the wireless device may proceed to Msg3 transmission of four-stepRACH procedure (e.g., in FIG. 13A). For example, the Msg3 that thewireless device transmit as a part of fallback procedure, comprises theCCCH SDU transmitted via MsgA. The MAC PDU comprising a MsgB indicatinga success of MsgA may not be multiplexed with a four-step RACH RAR(e.g., Msg 2).

For a two-step RA procedure, a wireless device may determine, at leastbased on a C-RNTI, whether a contention resolution is successful or notand/or whether Msg B is received successfully or not. The wirelessdevice may transmit, to a base station, MsgA comprising a C-RNTI (e.g.,C-RNTI MAC CE), e.g., if exists. For example, the wireless devicereceives, from the base station, a message comprising the C-RNTI priorto or before a transmission of the MsgA. The MsgA (or Transport block ofMsg A) may comprise a C-RNTI MAC CE indicating the C-RNTI. The wirelessdevice may start to monitor a downlink control channel for Msg Bcorresponding to the MsgA with one or more RNTIs, e.g., after or inresponse to transmitting the MsgA (or transmitting Transport block ofMsg A). For example, the wireless device may monitor a downlink controlchannel (e.g., PDCCH) with one or more RNTIs, after or in response totransmitting the MsgA indicating the C-RNTI (e.g., C-RNTI MAC CE). Theone or more RNTIs comprises the C-RNTI. The one or more RNTIs comprisesa first RNTI (e.g., msgB-RNTI) that may be determined (or calculated)based on uplink radio resources used for Msg A transmission. Forexample, the first RNTI is an RA-RNTI. For example, the first RNTI isthe one determined based on uplink radio resources used for Preambleand/or Transport block. For example, the uplink radio resources comprisetime (e.g., in terms of any combination of OFDM symbol, slot number,subframe number, and/or SFN) and/or frequency indexes of PRACH occasion(for Preamble transmission), a preamble identifier of Preamble, time(e.g., in terms of any combination of OFDM symbol, slot number, subframenumber, SFN, and/or time offset with respect to associated PRACHoccasion) and/or frequency indexes PUSCH occasion (for Transport blocktransmission), and/or DMRS index(es) (e.g., DMRS port identifier(s)) ofthe PUSCH occasion (for Transport block transmission). For example, thewireless device may monitor PDCCH(s) addressed to C-RNTI for a successresponse of MsgA and monitor PDCCH(s) addressed to the first RNTI (e.g.,msgB-RNTI) for a failure (or fallback) response of MsgA. The wirelessdevice may start a timer (e.g., contention resolution timer) and/ormonitor a downlink control channel while the timer is running. Forexample, the timer may be determine how long (e.g., a particular timeinterval or a period of time) the wireless device monitors the downlinkcontrol channel for receiving the MsgB corresponding to the MsgA (e.g.,a success response and/or a fallback response) from a base station,after or in response to transmitting the MsgA. The wireless device maystop monitoring the downlink channel, e.g., if the wireless devicereceives at least one response, e.g., PDCCH addressed to C-RNTI and/orPDCCH addressed to the first RNTI or RA-RNTI). The wireless device maydetermine that a contention resolution is successful based on one ormore conditions. For example, the wireless device determine that acontention resolution is successful, e.g., if a PDCCH addressed to theC-RNTI (i.e. C-RNTI included in MsgA) detected, and/or a PDSCH indicatedby the PDCCH (e.g., downlink assignment of DCI) is successfully decoded.The PDSCH may comprises at least one of a TA command (e.g., MAC CEcomprising one or more bits that indicates Timing Advanced Command)and/or a UL grant. The wireless device may stop monitoring the PDCCH,e.g., after or in response to determining that the contention resolutionis successful. Detecting the PDCCH addressed to the C-RNTI may be anindication of a success response (e.g., MsgB). Detecting the PDCCHaddressed to the C-RNTI and/or decoding the PDSCH indicated by the PDCCH(e.g., downlink assignment of DCI of the PDCCH) may be an indication ofa success response (e.g., MsgB). For example, the wireless device stopsthe monitoring of PDCCH addressed to the C-RNTI, e.g., if the wirelessdevice receives a fallback response (e.g., RAR). In this case, thecontention resolution is not successful, and the wireless device mayfallback to Msg3 transmission of a four-step RA procedure. The wirelessdevice may identify the fallback response based on a PDCCH addressed tothe first RNTI (e.g., msgB RNTI or RA-RNTI). For example, while thewireless device monitors the PDCCH, the wireless device detects thePDCCH addressed to the first RNTI (e.g., msgB RNTI or RA-RNTI). ThePDCCH addressed to the first RNTI may comprise a downlink assignmentbased on which the wireless device receives a PDSCH comprising thefallback response. The PDSCH comprising the fallback response maycomprise one or more responses. The wireless device identifies acorresponding response (e.g., success response, fallback response,and/or MsgB) from the one or more responses based on one or moreidentifiers. For example, the wireless device identifies thecorresponding response from the one or more responses, e.g., if anidentifier indicated by the corresponding response is matched to apreamble index of Preamble that the wireless device transmits. Thecorresponding response may comprise a field implicitly or explicitlyindicating whether the corresponding response is a success response or afallback response. The corresponding response may comprise an UL grantindicating uplink radio resource(s) where the wireless device transmitMsg3 based on the fallback operation. FIG. 19A (e.g. with FIG. 19B andFIG. 19C) is an example format of PDU of the PDSCH received based on thefirst RNTI. For example, RAPID in FIG. 19C is an example identifierbased on which the wireless device identifies the corresponding response(e.g., MAC RAR in FIG. 19A) for a fallback response. The wireless devicemay determine MsgB reception (or contention resolution or MsgAtransmission attempt) is failed, e.g., if neither fallback response norPDCCH addressed C-RNTI is detected within the timer (e.g., contentionresolution timer). The wireless device, in this case, may do back offoperation based on the backoff indicator (e.g., FIG. 19B), e.g., ifreceived in MsgB.

FIG. 23 is an example diagram illustrating a two-step RA procedure. Thewireless device may receive, from a base station, a message comprisingC-RNTI. The wireless device that has the C-RNTI may transmit, to thebase station, the C-RNTI (e.g., C-RNTI MAC CE indicating the C-RNTI) viaMsgA during the two-step RA procedure. For example, during the two-stepRA procedure, the wireless device may transmit MsgA comprising a firsttransmission of a preamble and a second transmission of a transportblock. The transport block may comprise the C-RNTI (e.g., C-RNTI MAC CEindicating the C-RNTI). The wireless device that transmits the C-RNTI(e.g., C-RNTI MAC CE indicating the C-RNTI) via the MsgA (or via thetransport block) may start to monitor a downlink control channel withone or more RNTIs. The one or more RNTIs may comprise the C-RNTI. Theone or more RNTIs may comprise msgB-RNTI. The one or more RNTIs maycomprise RA-RNTI. The wireless device may determine msgB-RNTI and/orRA-RNTI based on radio resources (e.g., in terms of time (e.g. OFDMsymbol, slot, subframe, and/or SFN numbers) and/or frequency indices)used for the first transmission and/or the second transmission. Thepreamble index and/or DMRS index (e.g., port or sequence index) used forthe second transmission may be used for the wireless device to determinethe msgB-RNTI and/or RA-RNTI. The wireless device may start a MsgB RARwindow (or a timer), e.g., after or in response to transmitting the MsgA(or Transport block). The wireless device may monitor the controlchannel during the MsgB RAR window or while the timer is running. Thewireless device may stop monitoring, e.g., if the wireless device mayreceive, via the downlink control channel and during the msgB RAR windowor while the timer is running, at least one PDCCH addressed to theC-RNTI and/or msgB-RNTI (or RA-RNTI). The wireless device may stopmonitoring, e.g., if the wireless device may receive, via the downlinkcontrol channel and during the msgB RAR window or while the timer isrunning, at least one PDCCH addressed to the C-RNTI and/or msgB-RNTI (orRA-RNTI) and/or if a PDSCH received based on a downlink assignment ofthe at least one PDCCH is successfully decoded.

FIG. 24A and FIG. 24B are example diagrams of a two-step RA procedure.The wireless device that has the C-RNTI may transmit, to the basestation, the C-RNTI (e.g., C-RNTI MAC CE indicating the C-RNTI) via MsgAduring the two-step RA procedure. The wireless device may start a MsgBRAR window (or a timer) after or in response to transmitting the MsgA(or Transport block). The wireless device may monitor the controlchannel during the MsgB RAR window or while the timer is running. Thewireless device that transmits the C-RNTI (e.g., C-RNTI MAC CEindicating the C-RNTI) via the MsgA may monitor a downlink controlchannel with C-RNTI and/or msgB-RNTI (or RA-RNTI). The wireless devicemay stop monitoring the downlink control channel, e.g., if the wirelessdevice receives at least one response (e.g., a success response or afallback response) during the MsgB RAR window or while the timer isrunning. For example, a detection of PDCCH addressed to the C-RNTI maybe the success response. For example, a detection of PDCCH addressed tothe C-RNTI and/or reception (e.g., success decoding) of a PDSCHindicated by the PDCCH addressed to the C-RNTI may be the successresponse. For example, receiving a

FIG. 24A is an example diagram showing that the wireless devicereceives, via the downlink control channel, a PDCCH addressed to C-RNTI.The wireless device that transmits the C-RNTI (e.g., C-RNTI MAC CEindicating the C-RNTI) via the MsgA may monitor a downlink controlchannel with C-RNTI and/or msgB-RNTI (or RA-RNTI). The wireless devicemay stop monitoring the downlink control channel with the C-RNTI and/ormsgB-RNTI (or RA-RNTI), e.g., after or in response to receiving (and/ordetecting) the PDCCH addressed to C-RNTI. In this case the wirelessdevice may determine, based on the detected PDCCH, that the two-step RAprocedure completes successfully, a reception of MsgB is successful,and/or a contention resolution completes successfully. The wirelessdevice may stop monitoring the downlink control channel with the C-RNTIand/or msgB-RNTI (or RA-RNTI), e.g., if the wireless device may receive(and/or detect), via the downlink control channel, the PDCCH addressedto the C-RNTI and/or msgB-RNTI (or RA-RNTI) and/or if a PDSCH receivedbased on a downlink assignment of the PDCCH is successfully decoded. Inan example, the detected PDCCH comprises a DCI comprising a downlinkassignment. The wireless device may, based on the downlink assignment,receive a PDSCH (e.g., MAC PDU). The received PDSCH (or MAC PDU) maycomprise a TA command (e.g., TA command MAC CE). The wireless device maystop monitoring the downlink control channel with the C-RNTI and/ormsgB-RNTI (or RA-RNTI), e.g., after or in response to receiving thePDCCH addressed to C-RNTI and/or the corresponding PDSCH (or MAC PDU)comprising the TA command (e.g., TA command MAC CE). In this case thewireless device may determine, based on the detected PDCCH and/or thesuccessfully decoded PDSCH (e.g., MAC PDU) that the two-step RAprocedure completes successfully, a reception of MsgB is successful,and/or a contention resolution completes successfully.

FIG. 24B is an example diagram illustrating that a wireless devicereceives, via the downlink control channel, a PDCCH addressed tomsgB-RNTI (or RA-RNTI). The wireless device that transmits the C-RNTI(e.g., C-RNTI MAC CE indicating the C-RNTI) via the MsgA may monitor adownlink control channel with C-RNTI and/or msgB-RNTI (or RA-RNTI). Thewireless device may stop monitoring the downlink control channel withthe C-RNTI and/or msgB-RNTI (or RA-RNTI), e.g., after or in response toreceiving the PDCCH addressed to msgB-RNTI (or RA-RNTI). The detectedPDCCH addressed to msgB-RNTI (or RA-RNTI) may comprise a DCI indicatinga downlink assignment of a PDSCH (e.g., MAC PDU). The wireless devicemay, based on the downlink assignment, receive the PDSCH (e.g., MACPDU). The received PDSCH (e.g., MAC PDU) may comprise one or moreresponses (e.g., one or more MsgBs). The wireless device may stopmonitoring the downlink control channel with the C-RNTI and/or msgB-RNTI(or RA-RNTI), e.g., after or in response to receiving the PDCCHaddressed to C-RNTI and/or the PDSCH (e.g., MAC PDU) received based onthe downlink assignment of the PDCCH. The PDSCH may comprise an RAR(e.g., a fallback response) of the MsgA. The wireless device mayidentify the RAR (e.g., MsgB) corresponding to the MsgA based on apreamble identifier matched to the preamble. For example, the RAR (e.g.,MsgB) may comprise at least one preamble identifier. The wireless devicemay determine that an RAR (e.g., MsgB) in the PDSCH (or MAC PDU)corresponds to the MsgA, e.g., at least based on a preamble identifierof the RAR (e.g., MsgB) matched to the preamble that the wireless devicetransmits to the base station via the MsgA. The RAR may indicate (e.g.,based on an implicit or explicit indication/field) a fallback to Msg3transmission of a four-step RA procedure. For example, the RAR maycomprise a UL grant and/or a TA command. The wireless device maytransmit Msg3 via radio resource(s) indicated by the UL grant with a ULtransmission timing adjusted based on the TA command. The Msg3 maycomprise at least a portion of transport block. For example, the Msg3and the transport block of the MsgA may be the same. For example, theMsg3 may comprise the C-RNTI.

FIG. 25 is an example diagram illustrating an two-step RA procedure. Thewireless device may transmit a MsgA comprising a first transmission of apreamble and a second transmission of a transport block. The transportblock may comprise CCCH SDU. The CCCH SDU may comprise an RRC(re)establishment request, an RRC setup request, and/or an RRC resumerequest. The wireless device that transmits the CCCH SDU via MsgA maynot receive a C-RNTI from a base station prior to transmitting the MsgA.The wireless device may start to monitor a downlink control channel witha particular RNTI. The wireless device may start a MsgB RAR window or atimer, e.g., after or in response to transmitting the MsgA (or Transportblock of the MsgA). The wireless device may monitor the control channelduring the MsgB RAR window or while the timer is running. The particularRNTI may be referred to as msgB-RNTI or RA-RNTI. The wireless device maydetermine the particular RNTI based on radio resources (e.g., in termsof time (e.g., OFDM symbol, slot, subframe, and/or SFN numbers) and/orfrequency indices) of the first transmission (e.g., for the preamble)and/or the second transmission (e.g., for the transport block). Thepreamble index and/or DMRS index (e.g., DMRS sequence and/or port index)may be used for the wireless device to determine the particular RNTI.The wireless device may detect and/or receive, during the MsgB RARwindow (or while the timer is running), a PDCCH addressed to theparticular RNTI. A DCI received via the PDCCH may comprise a downlinkassignment for receiving a PDSCH. The DCI may be a particular DCI whoseformat is predefined. For example, the DCI is a DCI format 1_0 or DCIformat 1_1. The wireless device may receive and/or decode the PDSCHbased on the downlink assignment. A MAC entity of the wireless devicemay receive an MAC PDU (e.g., parsed from the PDSCH) from a physicallayer of the wireless device. The physical layer may decode the PDSCHand sends data (e.g., the MAC PDU) decoded and/or parsed from the PDSCHto the MAC entity. The wireless device may identify a response (e.g.,MsgB) of the MsgA from the MAC PDU. For example, the response maycomprise a preamble identifier matched the preamble that the wirelessdevice transmits to the base station via the MsgA. The response may be asuccess RAR. The response may be a fallback RAR. There may be anexplicit or implicit indicator based on which the wireless deviceidentifies whether the received/identified response is a success RAR ora fallback RAR. For example, there is a field (e.g., the explicitindicator) indicating a type (success or fallback) of RAR. For example,the wireless device may identify the type of RAR (a success RAR or afallback RAR) based on a format of received RAR. For example, thesuccess RAR and/or the fallback RAR may comprise different type ofand/or different size of one or more fields. For example, the response(the success RAR or the fallback RAR) may comprise a second fieldindicating a length (or a size) of the response. The wireless device mayidentify, based on the second field, the type of RAR (the success RAR orthe fallback RAR).

In an example, a wireless device may transmit Preamble and Transportblock of MsgA for a two-step RA procedure. The Transport block maycomprise an RRC request (e.g., CCCH SDU). The RRC request (e.g., CCCHSDU) may comprise an RRC (re)establishment request, an RRC setuprequest, and/or an RRC resume request. The wireless device thattransmits the RRC request (e.g., the CCCH SDU) via MsgA may not receivea C-RNTI from a base station prior to transmitting the MsgA. TheTransport block (and/or the RRC request) may comprise a wireless deviceidentifier that may be used for a contention resolution. The wirelessdevice may receive MsgB (a PDSCH) as a success response or a fallbackresponse of the MsgA. The MsgB may comprise a response of the RRCrequest (e.g., CCCH SDU), e.g., if the MsgB is the success response ofthe MsgA. For example, the response of the RRC request (e.g., CCCH SDU)comprises an RRC message (e.g., SRB RRC message). The RRC message (e.g.,SRB RRC message) may comprise an RRC (re)establishment message (orconfiguration), an RRC setup message (or configuration), and/or an RRCresume message (or configuration) as responses of the RRC(re)establishment request, the RRC setup request, and/or the RRC resumerequest, respectively, that the wireless device transmits via MsgA (orTransport Block).

In an example, the RRC message (e.g., SRB RRC message) requires a largesize of message bits to be transmitted. A base station may not multiplex(or may multiplex a limited number of) one or more MsgBs for one or morewireless devices, e.g., if a MsgB comprises the RRC message (e.g., SRBRRC message). For example, MsgB received by a wireless device from abase station as a response (e.g., as a success response) of MsgA may besplit into a plurality of MsgBs. At least one of the plurality of MsgBsmay be multiplexed with one or more MsgBs (e.g., MsgBs of other wirelessdevice(s)). At least one of the plurality of MsgBs may be a wirelessdevice specific message (e.g., not multiplexed with a split MsgB ofother wireless device(s)).

For example, a wireless device may receive, from a base station, an MsgBas a response (e.g., as a success response) of MsgA. The MsgB maycomprise a success RAR (e.g., referred to as MsgB1 in thisspecification) and an RRC message (e.g., referred to as MsgB2 in thisspecification). The MsgB2 (e.g., the RRC message of the MsgB) maycomprise an RRC (re)establishment message (or configuration), an RRCsetup message (or configuration), and/or an RRC resume message (orconfiguration) as responses of the RRC (re)establishment request, theRRC setup request, and/or the RRC resume request, respectively. TheMsgB1 (e.g., the success RAR of the MsgB) may comprise one or morefields indicating at least one of: an identifier of a preamble, a ULgrant, a DL assignment, a TA command, and/or a contention resolutionidentifier. The MsgB1 (e.g., success RAR of the MsgB) and/or the MsgB2(e.g., the RRC message of the MsgB) may be multiplexed into an MAC PDUreceived by a wireless device as a response of MsgA. For example, theMsgB1 and the MsgB2 are multiplexed into the MAC PDU. A wireless devicemay receive the MsgB1 and the MsgB2 from separate PDSCHs. For example,the MsgB1 and the MsgB2 are not multiplexed into the MAC PDU. Forexample, a wireless device may receive a first PDSCH (e.g., a first MACPDU) multiplexing the MsgB1 and other wireless device(s)′ RARs (e.g.,Msg2, MsgB1s, and/or MsgB). For example, the wireless device may receivea second PDSCH (e.g., a second MAC PDU) comprising the MsgB2. The secondPDSCH may be a wireless device specific message for the wireless device.

A wireless device may transmit MsgA comprising an RRC request (e.g.,CCCH SDU). The wireless device may receive MsgB1 and MsgB2 via differentPDSCHs as a response of the MsgA. The MsgB1 may comprise at least oneof: a random access preamble Identifier (RAPID), a contention resolutionidentifier, C-RNTI, a TA command, a UL grant, and/or a downlinkassignment. The MsgB2 may comprise the RRC message (e.g., SRB RRCmessage). The MsgB2 may further comprise one or more information thatthe MsgB1 may not indicate (or comprise). For example, the MsgB2 maycomprise at least one of: comprise an RAPID, a contention resolutionidentifier, C-RNTI, a TA command, a UL grant, and/or a downlinkassignment. For example, the wireless device may receive a first PDSCHcomprising an MAC PDU multiplexing at least one MsgB1 (e.g., MACsubPDU).The MsgB1s may comprise at least one of: an RAPID, a TA command, and/orC-RNTI. The wireless device may identify the MsgB1 (or MacsubPDU) as aresponse corresponding to the MsgA, e.g., based on an RAPID of the MsgB1(e.g., MACsubPDU) matched to a preamble that the wireless devicetransmits via the MsgA. The wireless device may receive from the basestation a second PDSCH comprising the MsgB2. The MsgB2 may be thewireless device specific message, e.g., not multiplexed with otherwireless device responses. The MsgB2 may comprise the RRC message (e.g.,RRC (re)establishment message, RRC setup message, or RRC resume message)that may be a response of the RRC request (e.g., RRC (re)establishmentrequest, RRC setup request, or RRC resume request, respectively). Thewireless device may determine the contention resolution is successfullycompleted based on the contention resolution identifier of the MsgB1being matched to a wireless device identifier (ID) transmitted via theMsgA.

There may be one or more ways for a wireless device to receive MsgB1(e.g., a success RAR of MsgB) and/or MsgB2 (e.g., an RRA message ofMsgB). The wireless device may transmit MsgA comprising Preamble andTransport block (e.g., that may comprise a wireless device identifier)to a base station. The wireless device may receive a DCI (via a PDCCH)indicating a first downlink assignment of a first PDSCH. The wirelessdevice may receive the first PDSCH based on time/frequency resourceallocation indicated by the first downlink assignment. The receivedfirst PDSCH may comprise an MAC PDU comprising one or more MsgB1s. Forexample, the MAC PDU may further comprise one or more fallbackresponses. For example, the wireless device identifies MsgB1corresponding to the MsgA from the MAC PDU based on an RAPID thatmatched to the Preamble. For example, a MsgB1 (e.g., MACsubPDU) in theMAC PDU comprise a field (e.g., in a subheader of the MsgB1) indicatinga particular RAPID. If the particular RAPID is matched to the Preambletransmitted via the MsgA, the wireless device may determine that theMsgB1 is a response of the MsgA. The MsgB1 may further comprise acontention resolution identifier. In this case, the wireless device mayidentify MsgB1 corresponding to the MsgA from the MAC PDU based on theRAPID and/or the contention resolution identifier. For example, if theRAPID and/or the contention resolution identifier are matched to thePreamble and/or the wireless device identifier, respectively, thewireless device may determine that the MsgB1 is the response of theMsgA. In this case, the wireless device may determine that thecontention resolution is successfully completed based on the contentionresolution identifier matched to the wireless device identifier. TheMsgB1 may comprise a second downlink assignment of a second PDSCH thatmay comprise the MsgB2. For example, the second downlink assignment isnot indicated by a control signal (e.g., PDCCH and/or DCI). For example,the msgB1 (e.g., multiplexed in the MAC PDU) may indicate the seconddownlink assignment. In this case, an MAC entity of the wireless devicemay notify a physical layer of the wireless device of the seconddownlink assignment so that the physical layer of the wireless devicereceives the second PDSCH. The wireless device may receive the secondPDSCH based on the second downlink assignment. The second PDSCH maycomprise the MsgB2 that comprises the RRC message (e.g., RRC(re)establishment, RRC setup, or RRC resume) that may be a response ofthe CCCH SDU (e.g., RRC (re)establishment request, RRC setup request, orRRC resume request, respectively).

FIG. 26 is an example of two-step RA procedure. The wireless deviceinitiating the two-step RA procedure may transmit MsgA comprisingPreamble and Transport block. The Transport block may comprise an RRCrequest message (e.g., CCCH SDU). For example, the RRC request messagecomprise one of: an RRC (re)establishment request, RRC setup request,and/or RRC resume request. The wireless device may start to monitor adownlink control channel for MsgB1 and MsgB2, e.g., after or in responseto transmitting the MsgA. The Transport block (or the RRC requestmessage) may comprise a wireless device identifier that may be used fora contention resolution. The wireless device may start a window (or atimer) e.g., after or in response to transmitting the MsgA. The wirelessdevice may receive, during the window (or while the timer is running), aPDCCH comprising a DCI scheduling a first PDSCH. The PDCCH may beaddressed to (e.g., scrambled with) a particular RNTI. For example, thewireless device may determine the particular RNTI based on time and/orfrequency radio resource used for transmissions of Preamble and/orTransport Block. The wireless device may determine the particular RNTIfurther based on an RAPID of Preamble and/or DMRS information (e.g.,port number, sequence number, etc.) of Transport Block. The first PDSCHmay comprise an MAC PDU comprising MsgB1. There may be a plurality ofMsgB1s in the MAC PDU. The wireless device may identify the MsgB1 fromthe MAC PDU based on an RAPID. For example, the wireless devicedetermines the MsgB1 as a response of the MsgA, e.g., if the RAPIDindicated by a field (e.g., subheader) of the MsgB1 is matched to anidentifier of Preamble. The MsgB1 may further comprise a contentionresolution identifier. In this case, the wireless device may identifythe MsgB1 from the MAC PDU based on the RAPID and/or the wireless deviceidentifier. For example, the wireless device determines the MsgB1 as aresponse of MsgA, e.g., if the RAPID indicated by a first field (e.g.,subheader) of the MsgB1 is matched to an identifier of Preamble and/orthe contention resolution identifier indicated by a second field in theMsgB1 is matched to the wireless device identifier transmitted to thebase station via the Transport block (or the RRC request message). TheMsgB1 may further comprise a DL assignment. The DL assignment maycomprise a DL scheduling information. The wireless device may receive,based on the DL scheduling information, a second PDSCH. For example, theDL scheduling information indicates at least one of: time and/orfrequency radio resources indication (e.g., in terms of time and/orfrequency indexes) of DL transmission of the second PDSCH, a size (orlength) of transport block (or packet, or message) transmitted via thesecond PDSCH, and/or a modulation and coding scheme of the second PDSCH.The second PDSCH that the wireless device receives from the base stationmay comprise the MsgB2. The MsgB2 may comprise a response of the RRCrequest message transmitted via Transport block. For example, the MsgB2comprises at least one of: an RRC (re)establishment message, RRC setupmessage, or RRC resume message that may be a response of the CCCH SDU(e.g., RRC (re)establishment request, RRC setup request, or RRC resumerequest, respectively.

There may be one or more ways for a wireless device to receive MsgB1 andMsgB2. The wireless device may transmit MsgA comprising Preamble andTransport block to a base station. The Transport Block may comprise awireless device identifier. The wireless device may receive a first DCI(via a first PDCCH) indicating a first downlink assignment of a firstPDSCH. The wireless device may receive the first PDSCH based ontime/frequency resource allocation indicated by the first downlinkassignment. The received first PDSCH may comprise (or parsed as) an MACPDU comprising one or more MACsubPDUs. For example, at least one of theone or more MACsubPDUs may comprise the MsgB1. For example, the wirelessdevice identifies, based on an identifier of Preamble and from the oneor more MACsubPDUs, at least one of the one or more MACsubPDUs as theMsgB1 corresponding to the MsgA. The MsgB1 may further comprise acontention resolution identifier. In this case, the wireless device mayidentify the MsgB1 corresponding to the MsgA from the one or moreMACsubPDUs based on an RAPID that matches to an identifier of thePreamble and/or the contention resolution identifier of the MsgB1 thatmatches to the wireless device identifier. The MsgB1 may furthercomprise C-RNTI. The wireless device may monitor a downlink controlchannel based on the C-RNTI. The wireless device may receive, via thedownlink control channel, a second PDCCH comprising a second DCI. Thesecond PDCCH may be addressed to (or be scrambled with) the C-RNTI. Thesecond DCI may comprise a second downlink assignment of a second PDSCH.The second PDSCH may comprise the MsgB2. The wireless device may receivethe second PDSCH based on the second downlink assignment. The secondPDSCH may comprise the MsgB2 that comprises the RRC message (e.g., RRC(re)establishment, RRC setup, or RRC resume) that may be a response ofthe CCCH SDU (e.g., RRC (re)establishment request, RRC setup request, orRRC resume request, respectively).

FIG. 27 is an example of two-step RA procedure. The wireless deviceinitiating the two-step RA procedure may transmit MsgA comprisingPreamble and Transport block. The Transport block may comprise an RRCrequest message (e.g., CCCH SDU). For example, the RRC message compriseone of: an RRC (re)establishment request, RRC setup request, and/or RRCresume request. The wireless device may start to monitor a downlinkcontrol channel for MsgB1 and MsgB2, e.g., after or in response totransmitting the MsgA. The Transport block (or the RRC message) maycomprise a wireless device identifier that may be used for a contentionresolution. The wireless device may start a window (or a timer) e.g.,after or in response to transmitting the MsgA. The wireless device mayreceive, during the window (or while the timer is running), a firstPDCCH comprising a first DCI scheduling a first PDSCH. The first PDCCHmay be addressed to (e.g., scrambled with) a particular RNTI. Forexample, the wireless device may determine the particular RNTI based ontime and/or frequency radio resource used for transmissions of Preambleand/or Transport Block. The wireless device may determine the particularRNTI further based on an RAPID of Preamble and/or DMRS information(e.g., port number, sequence number, etc.) of Transport Block. The firstDCI may comprise a first downlink assignment that schedules a downlinkreception of the first PDSCH. The wireless device may receive the firstPDSCH based on the first downlink assignment. The first PDSCH maycomprise an MAC PDU comprising the MsgB1. For example, the MAC PDU maycomprise one or more MACsubPDUs. For example, at least one of the one ormore MACsubPDUs may comprise the MsgB1. The wireless device may identifythe MsgB1, from the one or more MACsubPDUs, based on an identifier ofPreamble. For example, the wireless device determines, among the one ormore MACsubPDUs, at least one of the one or more MACsubPDUs as the MsgB1(e.g., as a response of MsgA), e.g., if the RAPID indicated by a field(e.g., a field in a subheader) of the MsgB1 is matched to the identifierof Preamble. The MsgB1 may further comprise a contention resolutionidentifier. In this case, the wireless device may identify the MsgB1,from the one or more MACsubPDUs, based on the identifier of Preambleand/or the wireless device identifier. For example, the wireless devicedetermines, among the one or more MACsubPDUs, at least one of the one ormore MACsubPDUs as the MsgB1 (e.g., as a response of MsgA), e.g., if theRAPID indicated by a first field in the MsgB1 is matched to theidentifier of Preamble and/or the contention resolution identifierindicated by a second field in the MsgB1 is matched to the wirelessdevice identifier transmitted to the base station via the Transportblock (or the RRC request message). The MsgB1 may further comprise aparticular RNTI (e.g., RNTI in FIG. 27 ). For example, the particularRNTI is C-RNTI. The wireless device may monitor, based on the particularRNTI, a downlink control channel for a second PDSCH. The wireless devicemay detect a second PDCCH addressed to (or scrambled with) theparticular RNTI (e.g., C-RNTI). The second PDCCH may comprise a secondDCI. The second DCI may comprise a second downlink assignment of thesecond PDSCH. The second downlink assignment may comprise a DLscheduling information. The wireless device may receive, based on the DLscheduling information, the second PDSCH. For example, the DL schedulinginformation indicates at least one of: time and/or frequency radioresources indication (e.g., in terms of time and/or frequency indexes)of DL transmission of the second PDSCH, a size (or length) of transportblock (or packet, or message) transmitted via the second PDSCH, and/or amodulation and coding scheme of the second PDSCH. The second PDSCH thatthe wireless device receives from the base station may comprise theMsgB2. The MsgB2 may comprise a response of the RRC request messagetransmitted via Transport block. For example, the MsgB2 comprises atleast one of: an RRC (re)establishment message, an RRC setup message, oran RRC resume message that may be a response of the CCCH SDU (e.g., RRC(re)establishment request, RRC setup request, or RRC resume request,respectively.

In a two-step RA procedure, MsgB may comprise two responses, MsgB1 andMsgB2. A wireless device may receive a single PDSCH (e.g., a single MACPDU) comprising the MsgB1 and the MsgB2. A wireless device may receivethe MsgB1 and MsgB1 via different (or separate) PDSCHs (e.g., a firstPDSCH and a second PDSCH). The MsgB1 may comprise a contentionresolution identifier. The wireless device may determine, based on thecontention resolution identifier, whether a contention resolution issuccessful or not. For example, the wireless device may transmit MsgAcomprising Preamble and Transport block. The Transport block maycomprise a wireless device identifier of the wireless device. Thewireless device may determine that a contention resolution is successfulif the contention resolution identifier in the received MsgB1 is matchedto the wireless device identifier. The wireless device may attempt toreceive the MsgB2 after or in response to the contention resolutiondetermined as successful. The wireless device may receive the MsgB2after or in response to receiving the MsgB1 (e.g., with a successfuldecoding of the MsgB1) and/or the contention resolution determined assuccessful. The MsgB2 may comprise a response of RRC request transmittedvia the Transport block. For example, the wireless device may receivethe MsgB2 but fail to decode the MsgB2. For example, the wireless devicemay not setup a radio bearer (e.g., SRB and/or data radio bearer, DRB)to a network (or to a base station) if the wireless device fails todecode the MsgB2. The wireless device may not setup a radio bearer(e.g., SRB and/or DRB) with a network (or with a base station) if thewireless device does not receive the response of the RRC request (e.g.,RRC (re)establishment, RRC setup, or RRC resume). This may be a casethat the wireless device may determine that the contention resolution issuccessful but the wireless device may not setup, (re)establish, orresume a radio bearer (e.g., SRB and/or DRB) with a network (or with abase station)

The wireless device may attempt to receive another one or more MsgB2s ifthe wireless device fails to decode MsgB2. A two-step RA procedure maysupport HARQ process for receiving MsgB2. The wireless device may decodesecond MsgB2 successfully. The wireless device may transmit, to the basestation, an ACK indicator (e.g., UCI comprising the ACK indicator via aPUCCH) after or in response to decoding the second MsgB2 successfully.

For example, if the wireless device fails to decode MsgB2 (e.g., initialtransmission of MsgB2), the wireless device may transmit, to a basestation, an NACK indicator. For example, the wireless device transmits,to the base station via a PUCCH, UCI comprising the NACK indicator. ADCI that schedules a reception of the MsgB2 (e.g. initial transmissionof MsgB2) may indicate radio resource(s) of the PUCCH. The wirelessdevice may attempt to receive a second MsgB2 (e.g., retransmission ofMsgB2) after or in response to transmitting the NACK indicator. If thewireless device fails to decode the second MsgB2, the wireless devicemay transmit a second NACK indicator (e.g., using UCI) via a secondPUCCH. A second DCI that schedules a reception of the second MsgB2 (e.g.second transmission of MsgB2) may indicate radio resource(s) of thesecond PUCCH. The wireless device may attempt to receive a third MsgB2(e.g., retransmission of MsgB2) after or in response to transmitting thesecond NACK indicator. The wireless device may repeat this process Ntimes, e.g., until the wireless device successfully decodes the MsgB2based on N retransmissions of MsgB2.

A wireless device may monitor downlink control signaling in a regularmanner (e.g., in each slot and/or in each symbol) to receive uplinkgrants and/or downlink assignment. Monitoring the downlink controlsignaling in a regular manner may be beneficial, for example, in thatthe wireless device may react on changes in the traffic behavior. Thisbenefit may come at a cost in terms of power consumption. For example,packet data traffic may be burst. For example, the packet data trafficmay be occasional periods of transmission activity followed by longperiods of silence. To reduce a wireless device power consumption, aradio technology (e.g., Wifi, LTE and/or NR) may employ a mechanism fordiscontinuous reception (DRX).

According to example embodiments, a plurality of time(s), timeduration(s), time interval(s) for a DRX operation of a wireless device.The plurality of time(s), time duration(s), time interval(s) may bereferred to as and may be interchangeable with one or more differentways or names. For example, the on-duration used in the DRX operationmay be referred to as an on-duration, an on-duration of a DRX operation,a DRX on-duration and/or the like. For example, the active time used inthe DRX operation may be referred to as an active time, an active timeof a DRX operation, a DRX active time, and/or the like. The time (e.g.,a time duration and/or time interval) that the wireless device does notdetermines as the active time of the DRX operation may be referred to asan inactive time (of a DRX operation), a non-active time (of a DRXoperation), a DRX inactive time, a non-DRX-active time, and/or the like.For example, the inactivity timer used in the DRX operation may bereferred to as an inactivity (or non-activity) timer, an inactivity (ornon-activity) timer of a DRX operation, a DRX inactivity (ornon-activity) timer, and/or the like.

In an example, a wireless device may monitor a downlink channel (e.g.,downlink control channel) with a DRX cycle. The DRX cycle may bepredefined and/or configurable. The wireless device may, based on theDRX cycle, monitors a downlink control channel for downlink controlsignaling during a first time interval (e.g., an on-duration and/or anactive time). For example, the first time interval may be configurableand/or may be adjustable (e.g., extended) based on DL and/or ULtransmission(s). For example, a wireless device may adjust (e.g.,extend) the first time interval, e.g., if the wireless device receives auplink grant (e.g., for a new transmission and/or for a retransmission)and/or a downlink assignment. The wireless device may not monitor adownlink control channel (e.g., switch off a receiver circuitry) duringa second time interval. For example, the second time interval may not beoverlapped with the first time interval. For example, the second timeinterval may be a time (e.g., continuous, non-continuous, and/or acombination thereof) except the first time interval. The wireless devicemay reduce a power consumption based on monitoring the downlink controlchannel during a particular time interval (e.g., the first timeinterval). For example, the longer the cycle, the lower the powerconsumption. A base station may control/configure the cycle based on oneor more parameters described in this specification.

A wireless device may receive, e.g., from a base station, a controlmessage (e.g., RRC message, MAC CE, DCI, and/or a combination thereof)scheduling a reception and/or a transmission of data. In this case, thewireless device may be scheduled another reception and/or transmissionof data. In an example, a wireless device may be scheduled for aretransmission of data and/or a transmission of HARQ feedbacks. In anexample, a wireless device may receive a UL grant based on which thewireless device may transmit a certain amount of data in a buffer inusing one scheduling occasion. For example, the wireless device cannottransmit all the data in a buffer in using one scheduling occasion.Additional UL grant (e.g., scheduled transmission occasion) may berequired to transmit the remaining data in the buffer.

A wireless device in a DRX operation may wait until a next activityperiod, e.g., if the additional occasion(s) are not scheduled in acurrent activity period. This may result in delays. The wireless devicemay remain in an active state for a certain time (e.g., configurabletime) after being scheduled. For example, a wireless device may(re)start a timer (e.g., an inactivity timer), e.g., when the wirelessdevice receives scheduling information (e.g., a DL assignment and/or anUL grant). The wireless device (re)starting the timer (e.g., aninactivity timer) may keep monitoring a downlink control channel (e.g.,remain in active) until the timer expires.

A wireless device may perform a DRX operation based on one or moretimers. The one or more timers may be at least one of:drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL,drx-RetransmissionTimerUL, drx-ShortCycleTimer, drx-HARQ-RTT-TimerDLand/or drx-HARQ-RTT-TimerUL. A timer value of each of the one or moretimers may be defined in terms of a number of TTIs, e.g., a number ofOFDM symbols, a number of slots, a number of subframes, a number ofsystem frames, and/or the like. A timer value of each of the one or moretimers may be defined in terms of a time value, e.g., millisecond(s),microsecond(s), second(s), and/or the like.

FIG. 28 is an example of a DRX operation as per an aspect of an exampleembodiment of the present disclosure. A wireless device may receive amessage comprising configuration parameters. The configurationparameters may indicate duration(s) of a long DRX cycle and/or a shortDRX cycle. The wireless device may monitor, via one or more PDCCHmonitoring occasions, downlink control channel(s) for a first timeinterval (e.g., during a DRX on-duration and/or a DRX active time). Thewireless device may determine the one or more PDCCH monitoring occasionsbased on the configuration parameters. For example, the wireless devicedetermines the first time interval in the beginning of a DRX cycle(e.g., a long DRX cycle and/or a short DRX cycle). For example, theconfiguration parameters comprise a first timer value of a first timer.The wireless device may start the first time interval in response to thefirst timer expires (e.g., the first timer reaches the first timervalue). The wireless device may stop monitoring, e.g., if no PDCCH hasbeen received during the first time interval. For example, the wirelessdevice switches off a receiver circuitry, e.g., based on stoppingmonitoring. The wireless device may continue to monitor the downlinkcontrol channel(s), e.g., if the wireless device receives a PDCCH duringthe first time interval. For example, the wireless device may (re)starta second timer (e.g., an inactivity timer) with a second timer value(e.g., indicated by the configuration parameters) in response toreceiving the PDCCH during the first time interval. The wireless devicemay continue to monitor the downlink control channel(s) while the secondtimer is running (e.g., additional PDCCH monitoring occasions). Thewireless device may (re)start the second timer (e.g., an inactivitytimer), e.g., if the wireless device receives a PDCCH while the secondtimer is running. The wireless device may stop monitoring, e.g., if noPDCCH has been received, e.g., if the second timer expires. There may beone or more DRX cycles that the wireless device configures. For example,the one or more DRX cycles comprise a first DRX cycle and/or a secondDRX cycle. The first DRX cycle (e.g., a long DRX cycle) may be longerthan the second DRX cycle (e.g., a short DRX cycle). The first timeinterval may be configured in the first DRX cycle and/or the second DRXcycle. The second DRX cycle may be used for a periodic traffic pattern(e.g., voice over internet protocol service). The DRX operation with thesecond DRX cycle may be optional. The configuration parameters mayindicate whether the second DRX cycle is activated and/or configured.For example, a presence (e.g., activated/configured) and/or an absence(e.g., deactivated/non-configured) of parameter sets for the second DRXcycle in the configuration parameters may be an indication of whetherthe second DRX cycle is activated and/or configured. The wireless devicemay start to monitor the downlink control channel(s) (e.g., start thefirst time interval) in response to receiving a control message (e.g.,DRX command MAC CE). The wireless device may stop monitoring thedownlink control channel(s) (e.g., during the first time interval) inresponse to receiving a control message (e.g., DRX command MAC CE).

A wireless device may receive a control message (e.g., an RRC message)indicating one or more DRX configuration parameters. The wireless devicemay configure, based on the control message, a DRX (e.g., a DRXfunctionality and/or a DRX operation). The DRX (e.g., a DRXfunctionality and/or a DRX operation) may control a wireless device'sPDCCH monitoring activity. The wireless device's PDCCH monitoringactivity may be for one or more RNTIs of the wireless device receivedfrom a base station. The one or more RNTIs may be predefined. Forexample, the one or more RNTIs comprise at least one of: C-RNTI,CS-RNTI, INT-RNTI, SFI-RNTI, SP-CSI-RNTI, TPC-PUCCH-RNTI,TPC-PUSCH-RNTI, and/or TPC-SRS-RNTI. The wireless device may monitor adownlink control channel (e.g., PDCCH) discontinuously using the one ormore RNTIs and/or the one or more DRX configuration parameters, e.g., ifthe DRX is configured.

A wireless device may receive a control message (e.g., an RRC message)indicating one or more DRX configuration parameters. The one or more DRXconfiguration parameters may indicate at least one of following: aduration at the beginning of a DRX cycle (e.g., drx-onDurationTimer); adelay before starting the drx-onDurationTimer (e.g., drx-SlotOffset); aduration after the PDCCH occasion in which a PDCCH indicates a new UL orDL transmission for the MAC entity (e.g., drx-InactivityTimer); aduration (e.g., a maximum duration) until a DL retransmission isreceived (e.g., drx-RetransmissionTimerDL, for example, configured perDL HARQ process except for the broadcast process); a duration (e.g., amaximum duration) until a grant for UL retransmission is received (e.g.,drx-RetransmissionTimerUL, for example, configured per UL HARQ process);a Short DRX cycle or a duration of a short DRX cycle (e.g.,drx-ShortCycle, e.g., optionally configured); a duration where thewireless device follows the Short DRX cycle (e.g., drx-ShortCycleTimer,e.g., optionally configured); a duration (e.g., a minimum duration)before a DL assignment for HARQ retransmission is expected by the MACentity (e.g., drx-HARQ-RTT-TimerDL, e.g., configured per DL HARQ processexcept for the broadcast process); and/or a duration (e.g., a minimumduration) before a UL HARQ retransmission grant is expected by the MACentity (e.g., drx-HARQ-RTT-TimerUL, e.g., configured per UL HARQprocess). The one or more DRX configuration parameters may furtherindicate a long DRX cycle (e.g., a duration of a long DRX cycle. The oneor more DRX configuration parameters may further indicate a startingoffset (e.g., drx-StartOffset) based on which the wireless devicedetermines a TTI (e.g., a slot, a subframe, or a system frame) where thelong and short DRX Cycle starts. For example, the long DRX cycle and thestarting offset may be indicated by a single parameter, e.g.,drx-LongCycleStartOffset or by a plurality of parameters, e.g.,drx-LongCycle for the duration of the long DRX cycle and drx-StartOffsetfor the starting offset.

In an example, the control message (e.g., an RRC message) may comprise aDRX configuration information element (IE), e.g., DRX-Config. The DRXconfiguration IE (e.g., DRX-Config) may indicating the one or more DRXconfiguration parameters. An example of the DRX configuration IE (e.g.,DRX-Config) is as below:

DRX-Config ::= SEQUENCE {  drx-onDurationTimer CHOICE {subMilliSecondsINTEGER (1..31), milliSeconds ENUMERATED {ms1, ms2, ms3, ms4, ms5, ms6,ms8, ms10, ms20, ms30, ms40, ms50, ms60, ms80, ms100, ms200, ms300,ms400, ms500, ms600, ms800, ms1000, ms1200, ms1600, spare8, spare7,spare6, spare5, spare4, spare3, spare2, spare1 }}, drx-InactivityTimer ENUMERATED {ms0, ms1, ms2, ms3, ms4, ms5, ms6, ms8,ms10, ms20, ms30, ms40, ms50, ms60, ms80, ms100, ms200, ms300, ms500,ms750, ms1280, ms1920, ms2560, spare9, spare8, spare7, spare6, spare5,spare4, spare3, spare2, spare1},  drx-HARQ-RTT-TimerDL INTEGER (0..56), drx-HARQ-RTT-TimerUL INTEGER (0..56), drx-RetransmissionTimerDL ENUMERATED {sl0, sl1, sl2, sl4, sl6, sl8,sl16, sl24, sl33, sl40, sl64, sl80, sl96, sl112, sl128, sl160, sl320,spare15, spare14, spare13, spare 12, spare11, spare 10, spare9, spare8,spare7, spare6, spare5, spare4, spare3, spare2, spare1 }, drx-RetransmissionTimerUL ENUMERATED {sl0, sl1, sl2, sl4, sl6, sl8,sl16, sl24, sl33, sl40, sl64, sl80, sl96, sl112, sl128, sl160, sl320,spare15, spare14, spare13, spare 12, spare11, spare 10, spare9, spare8,spare7, spare6, spare5, spare4, spare3, spare2, spare1}, drx-LongCycleStartOffset CHOICE {   ms10 INTEGER(0..9),   ms20INTEGER(0..19),   ms32 INTEGER(0..31),   ms40 INTEGER(0..39),   ms60INTEGER(0..59),   ms64 INTEGER(0..63),   ms70 INTEGER(0..69),   ms80INTEGER(0..79),   ms128 INTEGER(0..127),   ms160 INTEGER(0..159),  ms256 INTEGER(0..255),   ms320 INTEGER(0..319),   ms512INTEGER(0..511),   ms640 INTEGER(0..639),   ms1024 INTEGER(0..1023),  ms1280 INTEGER(0..1279),   ms2048 INTEGER(0..2047),   ms2560INTEGER(0..2559),   ms5120 INTEGER(0..5119),   ms10240 INTEGER(0..10239)}, shortDRX SEQUENCE {  drx-ShortCycle ENUMERATED {ms2, ms3, ms4, ms5,ms6, ms7, ms8, ms10, ms14, ms16, ms20, ms30, ms32, ms35, ms40, ms64,ms80, ms128, ms160, ms256, ms320, ms512, ms640, spare9, spare8, spare7,spare6, spare5, spare4, spare3, spare2, spare1 }, drx-ShortCycleTimer INTEGER (1..16)} drx-SlotOffset INTEGER (0..31)}

In the example of the DRX configuration IE (e.g., DRX-Config) above,drx-HARQ-RTT-TimerDL may indicate a value of DRX HARQ round trip timerfor a downlink in number of symbols of the BWP where the transport blockwas received. For example, drx-HARQ-RTT-TimerDL indicates a duration(e.g., a minimum duration) before a DL assignment for HARQretransmission is expected by the MAC entity of the wireless device.drx-HARQ-RTT-TimerDL may be configured per DL HARQ process. The DL HARQprocess may not comprise a HARQ process for a broadcastingtransmission/signaling. drx-HARQ-RTT-TimerUL may indicate a value of DRXHARQ round trip timer for a uplink in number of symbols of the BWP wherethe transport block was transmitted. For example, drx-HARQ-RTT-TimerULindicates a duration (e.g., a minimum duration) before a UL HARQretransmission grant is expected by the MAC entity of the wirelessdevice. drx-HARQ-RTT-TimerUL may be configured per UL HARQ process.drx-InactivityTimer may indicate a duration after the PDCCH occasion inwhich a PDCCH indicates a new UL or DL transmission for the MAC entity.For example, drx-InactivityTimer indicates a value in multiple integersof 1 millisecond. ms0 corresponds to 0, ms1 corresponds to 1millisecond, ms2 corresponds to 2 milliseconds, and so on.drx-LongCycleStartOffset may indicate a duration of a long DRX cycle(e.g., drx-LongCycle) and a starting offset (e.g., drx-StartOffset)based on which the wireless device determines a TTI (e.g., a slot, asubframe, or a system frame) where the long and short DRX Cycle starts.A value of drx-LongCycle may be in millisecond. A value ofdrx-StartOffset may be in multiples of 1 millisecond. If drx-ShortCycleis configured, the value of drx-LongCycle may be a multiple of thedrx-ShortCycle value. For example, based on a choice of [ms10 INTEGER(0. . . 9)] in the example above, ms10 corresponds to drx-LongCycle andINTEGER(0 . . . 9) corresponds to drx-StartOffset. drx-onDurationTimermay indicate a duration at the beginning of a DRX cycle.drx-onDurationTimer may be a value in multiples of 1/32 milliseconds(e.g., subMilliSeconds) or in milliSecond. For example, a value ms1corresponds to 1 ms, value ms2 corresponds to 2 ms, and so on.drx-RetransmissionTimerDL may indicate a duration (e.g., a maximumduration) until a DL retransmission is received.drx-RetransmissionTimerDL may be configured per DL HARQ process exceptfor the broadcast process. drx-RetransmissionTimerDL may be a value innumber of slot lengths of the BWP where the transport block wasreceived. value sl0 corresponds to 0 slots, sl1 corresponds to 1 slot,sl2 corresponds to 2 slots, and so on. drx-RetransmissionTimerUL mayindicate a duration (e.g., a maximum duration) until a grant for ULretransmission is received. drx-RetransmissionTimerUL may be configuredper UL HARQ process. drx-RetransmissionTimerUL may be a value in numberof slot lengths of the BWP where the transport block was transmitted.sl0 corresponds to 0 slots, sl1 corresponds to 1 slot, sl2 correspondsto 2 slots, and so on. drx-ShortCycleTimer may indicate a duration wherethe wireless device follows the Short DRX cycle. drx-ShortCycleTimer maybe optionally configured. drx-ShortCycleTimer may be a value inmultiples of drx-ShortCycle. A value of 1 corresponds to drx-ShortCycle,a value of 2 corresponds to 2*drx-ShortCycle and so on. drx-ShortCyclemay indicate a short DRX cycle or a duration of a short DRX cycle.drx-ShortCycle may be optionally configured. drx-ShortCycle may be avalue in milliseconds. ms1 corresponds to 1 millisecond, ms2 correspondsto 2 milliseconds, and so on. drx-SlotOffset may indicate a delay beforestarting the drx-onDurationTimer. drx-SlotOffset may be a value in 1/32milliseconds. Value 0 corresponds to 0 millisecond, value 1 correspondsto 1/32 milliseconds, value 2 corresponds to 2/32 milliseconds, and soon.

In an example, when a DRX cycle (e.g., a long DRX cycle and/or a shortDRX cycle) is configured, an active time comprise a time (e.g., a timeduration) while: drx-onDurationTimer or drx-InactivityTimer ordrx-RetransmissionTimerDL or drx-RetransmissionTimerUL orra-ContentionResolutionTimer is running; or a scheduling request is senton PUCCH and is pending; or a PDCCH indicating a new transmissionaddressed to the C-RNTI of the wireless device has not been receivedafter successful reception of a random access response for the randomaccess preamble not selected by the wireless device among thecontention-based random access preamble. Based on evaluating one or moreconditions above, the wireless device may determine the active time.

In an example, a wireless device may start drx-HARQ-RTT-TimerDL for acorresponding HARQ process in a reference symbol (e.g., a first symbolafter the end of the corresponding transmission carrying the DL HARQfeedback), e.g., if a MAC PDU is received in a configured downlinkassignment. The wireless device may stop the drx-RetransmissionTimerDLfor the corresponding HARQ process, e.g., if a MAC PDU is received in aconfigured downlink assignment.

In an example, a wireless device may start drx-HARQ-RTT-TimerUL for acorresponding HARQ process in a reference symbol (e.g., a first symbolafter the end of the first repetition of the corresponding PUSCHtransmission), e.g., if a MAC PDU is transmitted in a configured uplinkgrant. The wireless device may stop drx-RetransmissionTimerUL for thecorresponding HARQ process, e.g., if a MAC PDU is transmitted in aconfigured uplink grant.

A wireless device may start drx-RetransmissionTimerDL for acorresponding HARQ process in a reference symbol (e.g., a first symbolafter the expiry of drx-HARQ-RTT-TimerDL). For example, a wirelessdevice starts drx-RetransmissionTimerDL for a corresponding HARQ processin a reference symbol (e.g., a first symbol after the expiry ofdrx-HARQ-RTT-TimerDL), e.g., if drx-HARQ-RTT-TimerDL expires and/or ifthe data of the corresponding HARQ process was not successfully decoded.

A wireless device may start the drx-RetransmissionTimerUL for thecorresponding HARQ process in a reference symbol (e.g., a first symbolafter the expiry of drx-HARQ-RTT-TimerUL). For example, the wirelessdevice starts the drx-RetransmissionTimerUL for the corresponding HARQprocess in a reference symbol (e.g., a first symbol after the expiry ofdrx-HARQ-RTT-TimerUL), e.g., if drx-HARQ-RTT-TimerUL expires.

A wireless device may stop drx-onDurationTimer and/or stopdrx-InactivityTimer. For example, the wireless device stopsdrx-onDurationTimer and/or stops drx-InactivityTimer, e.g., if a DRXCommand MAC CE or a Long DRX Command MAC CE is received.

A wireless device may start (or restart) drx-ShortCycleTimer in a firstreference symbol (e.g., a first symbol after an expiry ofdrx-InactivityTimer) or in a second reference symbol (e.g., a firstsymbol after the end of DRX Command MAC CE reception) and employ (e.g.,use) the Short DRX Cycle. For example, if the Short DRX cycle isconfigured, the wireless device may start (or restart)drx-ShortCycleTimer in the first reference symbol or in the secondreference symbol and employ (e.g., use) the Short DRX Cycle, e.g., ifdrx-InactivityTimer expires or a DRX Command MAC CE is received. Forexample, if the Short DRX cycle is not configured, the wireless devicemay employ (e.g., use) the Long DRX cycle. For example, if the Short DRXcycle is configured, the wireless device may employ (e.g., use) the longDRX cycle, e.g., if drx-InactivityTimer does not expires and/or a DRXCommand MAC CE is not received.

A wireless device may employ (e.g., use) the Long DRX cycle, e.g., ifdrx-ShortCycleTimer expires. A wireless device may stopdrx-ShortCycleTimer and/or employ (e.g., use) the Long DRX cycle, e.g.,if a Long DRX Command MAC CE is received.

A wireless device may start drx-onDurationTimer after or in response todrx-SlotOffset from the beginning of a reference subframe. The wirelessdevice may determine the reference subframe based on a predefinedformula and/or based on a received parameter indicating the referencesubframe. For example, the wireless device may determine the referencesubframe, e.g., based on [(SFN×10)+subframe number] modulo(drx-ShortCycle)=(drx-StartOffset) modulo (drx-ShortCycle) wheresubframe number indicate the reference subframe if the Short DRX Cycleis used. For example, the wireless device may determine the referencesubframe, e.g., based on [(SFN×10)+subframe number] modulo(drx-LongCycle)=drx-StartOffset where the subframe number indicate thereference subframe if the Long DRX Cycle is used.

A wireless device may monitor a PDCCH, e.g., if the wireless device isin Active Time. The wireless device may start and/or stop differenttimers based on whether the PDCCH indicates a DL transmission or a ULtransmission and/or based on whether the PDCCH indicates a newtransmission. For example, if the PDCCH indicates a DL transmission, thewireless device starts drx-HARQ-RTT-TimerDL for a corresponding HARQprocess in a reference symbol (e.g., a first symbol after the end of thecorresponding transmission carrying the DL HARQ feedback) and/or stopdrx-RetransmissionTimerDL for the corresponding HARQ process. Forexample, if the PDCCH indicates a UL transmission, the wireless devicemay start drx-HARQ-RTT-TimerUL for a corresponding HARQ process in areference symbol (e.g., a first symbol after the end of the firstrepetition of the corresponding PUSCH transmission) and/or stopdrx-RetransmissionTimerUL for the corresponding HARQ process. Forexample, if the PDCCH indicates a new transmission (DL or UL), thewireless device starts or restarts drx-InactivityTimer in a referencesymbol (e.g., a first symbol after the end of the PDCCH reception). ThePDCCH may not be a complete PDCCH occasion. Whether to monitor such aPDCCH of the incomplete PDCCH occasion may be an implementation. Forexample, a wireless device does not monitor a PDCCH of an PDCCHoccasion, e.g., if the active time starts or ends in the middle of thePDCCH occasion. For example, a wireless device monitors a PDCCH of anPDCCH occasion, e.g., if the active time starts or ends in the middle ofthe PDCCH occasion.

A wireless device may not transmit an SRS during a DRX operation. Forexample, the SRS may be an aperiodic SRS, a periodic SRS and/orsemi-persistent SRS. For example, the wireless device does not transmitthe SRS via a symbol n, e.g., if the wireless device is not be in anactive time considering DL or UL grants/assignments/DRX Command MACCE/Long DRX Command MAC CE received and/or a scheduling request sentuntil a time period (e.g., 4 milliseconds) prior to the symbol n whenevaluating one or more conditions determining the active time asdescribed in this specification.

A wireless device may not transmit (or report) CSI via PUCCH during aDRX operation. For example, the CSI may be an aperiodic CSI, a periodicCSI and/or semi-persistent CSI transmitted via PUCCH. For example, theCSI may be an aperiodic CSI, a periodic CSI and/or semi-persistent CSItransmitted via PUSCH. For example, the wireless device does nottransmit (or report) CSI e.g., in a symbol n if drx-onDurationTimer isnot running considering grants/assignments/DRX Command MAC CE/Long DRXCommand MAC CE received until a time period (e.g., 4 milliseconds) priorto symbol n when evaluating one or more conditions determining an activetime as described in this specification. For example, the wirelessdevice does not transmit (or report) CSI, e.g., if CSI masking (e.g.,csi-Mask) is configured by upper layers (e.g., by an RRC parameter)and/or in a symbol n if drx-onDurationTimer is not running consideringgrants/assignments/DRX Command MAC CE/Long DRX Command MAC CE receiveduntil a time period (e.g., 4 milliseconds) prior to symbol n whenevaluating one or more conditions determining the active time asdescribed in this specification. For example, the wireless device doesnot transmit (or report) CSI in a symbol n, e.g., if the wireless deviceis not in Active Time considering grants/assignments/DRX Command MACCE/Long DRX Command MAC CE received and/or a scheduling request sentuntil a time period (e.g., 4 milliseconds) prior to symbol n whenevaluating one or more conditions determining the active time asdescribed in this specification. For example, the wireless device doesnot transmit (or report) CSI, e.g., if CSI masking (e.g., csi-Mask) isconfigured by upper layers (e.g., by an RRC parameter) and/or in asymbol n if the wireless device is not in an active time consideringgrants/assignments/DRX Command MAC CE/Long DRX Command MAC CE receivedand/or a scheduling request sent until a time period (e.g., 4milliseconds) prior to symbol n when evaluating one or more conditionsdetermining the active time as described in this specification. Awireless device may transmit, to a base station, a particular signalduring a DRX operation. The particular signal may comprise HARQfeedback, aperiodic CSI on PUSCH, and/or aperiodic SRS. For example, thewireless device may transmit HARQ feedback, aperiodic CSI on PUSCH,and/or aperiodic SRS regardless of whether the wireless device ismonitoring PDCCH or not (e.g., regardless of whether the wireless deviceis in the active time or not).

A wireless device may perform a DRX operation while performing an RAprocedure. In an existing technology, a wireless device (e.g.,configured with a long DRX cycle and/or a short DRX cycle) maydetermine, as an active time of the DRX operation, one or more timeduration. For example, the one or more time duration comprises a timeduration while ra-ContentionResolutionTimer is running for a four-stepRA procedure. For example, the one or more time duration comprises asecond time duration between a first time and a second time. Forexample, the first time is after or in response to a successfulreception of a random access response for a preamble. For example, thepreamble is not selected by an MAC layer entity of the wireless deviceamong the contention-based random access preamble(s). For example, thewireless device may transmit (or select) the preamble for acontention-free RA procedure in FIG. 13B. For example, the preamble isselected based on an identifier of the preamble indicated by a controlmessage (e.g. PDCCH order, and/or RRC message, Handover command)transmitted by a base station. For example, the second time is when orin response to a PDCCH indicating a new transmission addressed to theC-RNTI of the wireless device has not been received after successfulreception of a random access response for the preamble not selected bythe MAC layer entity of the wireless device among the contention-basedrandom access preamble(s). The second time duration may be a timeduration starting after or in response to determining a successfulreception of a random access response of a preamble transmitted for thecontention-free RA procedure (e.g., FIG. 13B) until the wireless devicereceive a PDCCH indicating a new transmission addressed to the C-RNTI ofthe wireless device.

FIG. 29A is an example of an active time of the DRX operation. Awireless device may initiate a four-step RA procedure. the four-step RAprocedure may be a contention-based four-step RA procedure (e.g., FIG.13A). The wireless device may transmit, to a base station, an Msg1(e.g., a preamble). The wireless device may start to monitor, based onan RA-RNTI, a downlink control channel for an Msg2 (e.g., RAR) during anRAR window. The wireless device may receive a PDCCH (that is addressedto the RA-RNTI) indicating a DL assignment of an PDSCH during the RARwindow. The wireless device may receive, based on the DL assignment, thePDSCH. The wireless device may identify, from the PDSCH, the Msg2 basedon a field (e.g., a field of a subheader) indicating an RAPID matched toan identifier of the preamble. The Msg2 may comprise a UL grant for anMsg3 transmission. The Msg2 may comprise a TC RANTI for an Msg4reception (or for receiving a response of the Msg3 transmission). Thewireless device may transmit, based on the UL grant, an Msg3. Thewireless device may start a contention resolution timer after or inresponse to transmitting the Msg3. The wireless device may determine, asan active time, a time while the contention resolution timer is running.The wireless device may monitor PDCCH with the TC-RNTI for an Msg4reception (or for receiving a response of the Msg3 transmission) whilethe contention resolution timer is running. The wireless device maymonitor the PDCCH with one or more RNTIs for the DRX operation duringthe active time (e.g., while the contention resolution timer isrunning). The one or more RNTIs may, if the wireless device receives(e.g., is configured/assigned with) the one or more RNTIs, comprise atleast one of: C-RNTI, CS-RNTI, INT-RNTI, SFI-RNTI, SP-CSI-RNTI,TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, and/or TPC-SRS-RNTI. The wireless devicemay receive the PDCCH addressed to the TC-RNTI. The PDCCH may comprise aDL assignment for receiving an Msg4. The wireless device may receive theMsg4 based on the DL assignment. The wireless device may stop thecontention resolution timer, e.g., if the Msg4 comprise a contentionresolution identifier matched to a wireless device identifier that istransmitted via the Msg3. The wireless device may transmit C-RNTI (e.g.,C-RNTI MAC CE) via the Msg3. In this case, the wireless device maydetermine the contention resolution is successful, e.g., if the wirelessdevice receive the PDCCH addressed to the C-RNTI. The wireless devicemay stop the contention resolution timer, e.g., if the wireless devicereceive the PDCCH addressed to the C-RNTI and/or if the wireless devicedetermines the contention resolution is successful

FIG. 29B is an example of an active time of the DRX operation. Awireless device may initiate a contention free RA procedure comprisingan Msg1 transmission and an Msg2 reception (e.g., FIG. 13B). Thewireless device may receive a control message (e.g., an RRC message or aPDCCH order or a handover command) initiating the contention-free RAprocedure. The control message may indicate an identifier of a preamblefor the Msg1 transmission. The wireless device may transmit the preamblevia the Msg1 transmission. The wireless device may start to monitor,based on a particular RNTI, a downlink control channel for the Msg2reception (e.g., RAR reception) during an RAR window. For example, theparticular RNTI may be an RA-RNTI and/or C-RNTI. The wireless device mayreceive a PDCCH (e.g., that is addressed to the particular RNTI)indicating a DL assignment of an PDSCH during the RAR window. Thewireless device may receive, based on the DL assignment, the PDSCH. Thewireless device may identify, from the PDSCH, the Msg2 based on a fieldindicating an RAPID matched to the identifier of the preamble. Thewireless device may determine that the Msg2 (e.g., an RAR) reception issuccessful based on the RAPID matched to the identifier of the preamble.The wireless device may determine that the contention free RA procedureis successfully complete based on the Msg2 (e.g., an RAR) receptionbeing successful. The wireless device may determine, as an active time,a time while a PDCCH indicating a new transmission addressed to theC-RNTI of the wireless device has not been received after successfulreception of the RAR for the preamble not selected by the wirelessdevice among the contention-based random access preamble (or for thepreamble indicated by the control message). The wireless device maymonitor the PDCCH with one or more RNTIs for the DRX operation duringthe active time. The one or more RNTIs may, if the wireless devicereceives (e.g., is configured/assigned with) the one or more RNTIs,comprise at least one of: C-RNTI, CS-RNTI, INT-RNTI, SFI-RNTI,SP-CSI-RNTI, TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, and/or TPC-SRS-RNTI.

In the existing DRX technology, the wireless device may determine anactive time differently based on whether the wireless device performs acontention-based RA procedure (e.g., FIG. 13A) or a contention-free RAprocedure (e.g., FIG. 13B). For example, a wireless device determines,as an active time of a DRX operation of the wireless device, a time(e.g., a time duration) while ra-ContentionResolutionTimer is runningfor the contention-based RA procedure. For example, a wireless devicedetermine, as an active time for a contention-free RA procedure, a time(e.g., a time duration) while a PDCCH indicating a new transmissionaddressed to the C-RNTI of the wireless device has not been receivedafter successful reception of a random access response for the randomaccess preamble not selected by the wireless device among thecontention-based random access preamble. This may be because a number oftransmissions and receptions of the contention-based RA procedure isdifferent from that of the contention-free RA procedure. For example,the contention-based RA procedure comprise at least two transmissions(e.g., Msg1 and Msg3) and at least two receptions (e.g., Msg2 and Msg4).For example, the contention-free RA procedure comprise at least onetransmission (e.g., Msg1) and at least one reception (e.g., Msg2)without supporting an HARQ process for the at least one reception (e.g.,Msg2).

In a two-step RA procedure (e.g., FIG. 13B), a number of transmissionsand receptions may be the same for a contention-based two-step RAprocedure and a contention-free two-step RA procedure. For example, thetwo-step RA procedure may comprise at least one transmission (e.g.,MsgA) and at least one reception (e.g., MsgB). The two-step RA proceduremay be different number of transmissions and/or receptions based on whatinformation is indicated by a transport block of the MsgA and/or basedon what information is indicated by the MsgB as a response of the MsgA.For example, if the wireless device transmits C-RNTI via MsgA (e.g.,transport block of the MsgA), the wireless device may monitor, during anMsgB RAR window, a downlink control channel for a MsgB. For example, ifthe wireless device transmits an RRC request message via MsgA (e.g.,transport block of the MsgA), the wireless device may monitor, during anMsgB RAR window, a downlink control channel for a MsgB. The MsgB maycomprise an MsgB1 and an MsgB2. The wireless device may receive theMsgB1 and the MsgB2 via the same MAC PDU. The wireless device mayreceive the MsgB1 and the MsgB2 via different MAC PDUs (e.g., differentPDSCHs). The wireless device may not determine whether the wirelessdevice receive the MsgB1 and MsgB2 via the same MAC PDU or via differentMAC PDUs (e.g., different PDSCHs) before or until the wireless devicereceives a first MAC PDU (e.g., a first PDSCH) comprising the MsgB1. Thewireless device may determine, based on one or more indicators of theMsgB1 and/or the first MAC PDU, whether the MsgB2 is in the first MACPDU or in a second MAC PDU that the wireless device receives after or inresponse to receiving the first MAC PDU.

In an existing implementation of two-step random access procedures, awireless device may transmit a message (e.g., MsgA) comprising apreamble and a transport block (e.g., FIG. 13C). In an example, thewireless device may transmit the message (e.g., MsgA) while it is not ina DRX active time. The wireless device may start an MsgB RAR windowafter or in response to transmitting the message. The wireless devicemay determine that an inactive time of a DRX operation may comprise (anactive time of the DRX operation may not comprise) time while an MsgBRAR window is running. For example, the wireless device may stay ininactive time during the MsgB RAR window. For example, the wirelessdevice may transition to an inactive time (not Active Time) of a DRXoperation in response to starting the MsgB RAR window.

The problem for a two-step random access procedure arises when awireless device receives a response to a message (e.g., MsgA) during anMsgB RAR window while the wireless device is not in Active Time. In thiscase, the wireless device may stop monitoring a downlink control channelin response to receiving the response. For example, the wireless devicemay stop the MsgB RAR window in response to receiving the response. Forexample, the wireless device may determine, in response to receiving theresponse, that the two-step random access procedure successfullycompletes. Stopping monitoring the downlink control channel in responseto receiving the response may cause a transmission delay or acommunication failure of UL data or DL data. For example, the responseto the message may comprise a UL grant for PUSCH or DL assignment forPDSCH. The PUSCH or the PDSCH may require one or more retransmissions.The wireless device may discard (or drop) the UL data or the DL datafrom the buffer (e.g., due to a delay constraint) or may wait until anext on-duration occasion of a DRX operation. This results in increasinga packet drop (or loss) rate and/or a latency of UL and/or DLtransmissions. Two-step random access procedures may be implemented fortransmission of high priority, low latency traffic such as URLLC, andV2X signaling. This problem does not apply to a four-step random accessprocedure, as random access response may not be as critical and delaytolerant. In an example, a wireless device may enter (or transition to)a DRX inactive time or state (e.g., during which the wireless devicedoes not monitor the downlink control channel) during or after a randomaccess preamble is transmitted.

According to example embodiments, a wireless device may determine thatan active time of a DRX operation comprises one or more time intervals(or time durations) that start during the two-step RA procedure.According to example embodiments, the wireless device may determine theactive time based on a transmission of MsgA in the two-step RAprocedure. For example, the wireless device may start the active time inresponse to transmitting the MsgA. For example, the wireless device mayremain in the active time in response to transmitting the MsgA. Forexample, the wireless device may determine, as the active time, the timewhile the wireless device monitoring a PDCCH for a response to a MsgA.For example, the wireless device may determine that the active timecomprises time while the MsgB RAR window is running. In this case, thewireless device may start (or trigger) one or more DRX timers during orafter the two-step RA procedure. For example, the one or more DRX timersmay comprise drx-HARQ-RTT-TimerUL or drx-HARQ-RTT-TimerDL,drx-RetransmissionTimerUL, drx-RetransmissionTimerDL, drx-inactivitytimer, drx-onDurationTimer, and/or drx-shortcycletimer. For example,according to example embodiments, the wireless device startsdrx-HARQ-RTT-TimerDL or drx-HARQ-RTT-TimerDL in response to the responsecomprising a UL grant or a DL assignment, e.g., if the wireless devicereceives the response during a DRX active time.

According to example embodiment, the wireless device may startdrx-RetransmissionTimerUL in response to an expiry ofdrx-HARQ-RTT-TimerUL. For example, the wireless device may startdrx-RetransmissionTimerDL in response to an expiry ofdrx-HARQ-RTT-TimerDL. The wireless device may determine, as an activetimer of a DRX operation, time while drx-RetransmissionTimerUL and/ordrx-RetransmissionTimerUL are running. The wireless device may monitorone or more downlink control channels during the active time. Thewireless device may receive a grant (e.g., UL grant or DL assignment)for one or more retransmissions via the one or more downlink controlchannels during the active time.

The wireless device may, based on the one or more DRX timers, monitorthe downlink control channel and may receive a grant (e.g., UL grant(s)or DL grant(s)) that schedules one or more retransmissions of PUSCH orPDSCH scheduled by the response. For example, the wireless device mayreceive, via radio resource(s) indicated by the DL assignment,configuration parameter(s) (e.g., parameter(s) for beam management,URLCC and/or V2X traffic). The example embodiments enable a base station(or network) to provide the wireless device with UL grant(s) or DLassignment(s) for (re)transmission of PUSCH or PDSCH scheduled by theresponse to the MsgA. Example embodiments reduce a packet transmissionlatency problem of the existing two-step random access procedures andexisting DRX operations (procedures, technologies and/or processes).Example embodiments may increase battery power consumption andprocessing requirements for a wireless device, but it reduces a packettransmission delay for two-step random access procedures. For example,example embodiments may reduce a delay and a packet loss for URLCC andV2X traffic. For example, according to example embodiments, the wirelessdevice in example embodiments may receive UL grant(s) or DL grant(s) for(re)transmission after the two-step RA procedure without waiting for anext DRX on-duration occasion(s). This result in reducing a packet lossdue to high latency. In an example, a DRX timer (e.g.drx-HARQ-RTT-TimerUL and/or drx-HARQ-RTT-TimerDL) may start during thetwo-step random access procedure. The wireless device may continuemonitoring the downlink control channel and/or may successfully toreceive a grant (e.g., the UL grant(s) or the DL grant(s)) thatschedules the one or more retransmissions. In an example embodiment, awireless device may maintain the existing DRX operations for a four-steprandom access procedure. In an example, a wireless device may be in DRXinactive time while an RAR window (e.g., ra-ResponseWindow) for thefour-step random access procedure is running. The existing DRX operationfor the four-step random access procedure reduces battery powerconsumption. A wireless device may re-initiate a random access procedure(e.g., two-step random access procedure or four-step random accessprocedure), if needed, e.g., when the wireless device is in a DRX activetime.

In an example embodiment, the wireless device may receive, via one ormore downlink control channels during a DRX active time, a response(e.g. MsgB) to the MsgA of a two-step random access procedure (e.g.,FIG. 13C). The wireless device may stop monitoring one or more downlinkcontrol channels based on determining that the DRX operation is not inthe active time in response to receiving the response that may confirmssuccessful transmission of a transport block (e.g. URLLC, V2X packet) ofthe MsgA. The wireless device may transition to a DRX inactive time inresponse to receiving the response. This enhanced DRX procedure mayreduce batter power consumption, as the wireless device transitions tothe DRX inactive time in response to receiving the response, whilereducing packet transmission delay and loss as the wireless deviceremained in a DRX active time during an MsgB RAR window. The wirelessdevice in the example embodiment may start one or more DRX timers (e.g.,drx-HARQ-RTT-TimerUL or drx-HARQ-RTT-TimerUL). The wireless device maydetermine a proper timing or time interval (duration) to monitor the oneor more downlink control channels based on starting the one or more DRXtimers. For example, the wireless device may not monitor the one or moredownlink control channels, for example to save the batter power, whilethe one or more DRX timers are running. The wireless device may start tomonitor the one or more downlink control channels in response to the oneor more DRX timers expire.

According to an example embodiment, a wireless device may determine, asan active time, a time during a msgB RAR window. For example, thewireless device may start the msgB RAR window with a first time offsetfor a contention-based two-step RA procedure. For example, the wirelessdevice may start the msgB RAR window with a first time offset for acontention-free two-step RA procedure. For example, the wireless devicemay start the msgB RAR window after or in response to transmitting MsgA(or transport block of MsgA). The first time offset may be predefined asa first value (e.g., zero). For example, the first time offset may be areference symbol (e.g., first symbol or firstly located symbol in time)of a CORESET. For example, the CORESET is the earliest CORESET that isat least one or more symbols (e.g., at least one symbol) after a lastsymbol of a preamble transmission occasion of the preamble. For example,the CORESET is the earliest CORESET that is at least one or more symbols(e.g., at least one symbol) after a last symbol of a transport block(and/or MsgA) transmission occasion of the transport block (and/orMsgA). The MsgA may comprise an RRC request message. The MsgA maycomprise a C-RNTI (e.g., C-RNTI MAC CE). The wireless device may stopthe msgB RAR window in response to receiving a response (e.g., a PDSCHcomprising an MsgB) of the MsgA. The wireless device may stop the msgBRAR window in response to receiving a PDCCH comprising a DL assignment.The wireless device may receive, based on the DL assignment, theresponse (e.g., a PDSCH comprising an MsgB) of the MsgA. The wirelessdevice may determine, as an active time, a time during a msgB RAR window

According to an example embodiment, a wireless device may determine anactive time during a two-step RA procedure, independent of a msgB RARwindow. For example, the two-step RA procedure is a contention-basedtwo-step RA procedure. For example, the two-step RA procedure is acontention-free two-step RA procedure. The wireless device may start aduration of an active time after or in response to transmitting MsgA (ortransport block of MsgA). The MsgA may comprise an RRC request message.The MsgA (e.g., transport block of MsgA) may comprise a wireless deviceidentifier for a contention resolution. The MsgA may comprise a C-RNTI(e.g., C-RNTI MAC CE). The wireless device may determine the active timeuntil (e.g., stop the active time in response to) receiving a response(e.g., a PDSCH comprising an MsgB) of the MsgA. The wireless device maydetermine the active time (and/or stop the active time) until or inresponse to receiving a PDCCH comprising a DL assignment. The wirelessdevice may receive, based on the DL assignment, the response (e.g., aPDSCH comprising an MsgB) of the MsgA. The wireless device maydetermine, as an active time, a time duration between a first time and asecond time. The first time may be after or in response to transmittingthe MsgA. The second time may be in response to receiving a response(e.g., a PDSCH comprising an MsgB) of the MsgA. The second time may bein response to receiving a PDCCH comprising a DL assignment. Thewireless device may receive, based on the DL assignment, the response(e.g., a PDSCH comprising an MsgB) of the MsgA.

FIG. 30A is an example of a DRX operation. The wireless device mayinitiate a two-step RA procedure. The two-step RA procedure may be acontention-based two-step RA procedure. For example, for thecontention-based two-step RA procedure, a preamble transmitted by thewireless device via MsgA is selected by an MAC layer of the wirelessdevice among the one or more preambles assigned (or configured orallocated) for the contention-based two-step RA procedure. The two-stepRA procedure may be a contention-free two-step RA procedure. Forexample, for the contention-free two-step RA procedure, a preambletransmitted by the wireless device via MsgA is not selected by an MAClayer of the wireless device among the one or more preambles assigned(or configured or allocated) for the contention-based two-step RAprocedure. The wireless device may transmit a preamble and a transportblock as a transmission of an MsgA. The wireless device may start tomonitor a downlink control channel for a response of the MsgA. Thewireless device may monitor the downlink control channel based on aC-RNTI, e.g., if the transport block comprises the C-RNTI (e.g., C-RNTIMAC CE). The wireless device may monitor the downlink control channelbased on a msgB RNTI (or RA-RNTI), e.g., if the transport blockcomprises an RRC request message (e.g., CCCH SDU) (and/or the transportblock does not comprise the C-RNTI (e.g., C-RNTI MAC CE)). The wirelessdevice may receive a first PDCCH via the downlink control channel. Thewireless device may receive the first PDCCH during a msgB RAR windowstarting in response to transmitting the MsgA (or transport block of theMsgA). The first PDCCH (e.g., DCI) may indicate a DL assignment forreceiving a PDSCH (e.g., MsgB). The first PDCCH (e.g., DCI) may beaddressed to the C-RNTI, e.g., if the wireless device transmits theC-RNTI via the MsgA. The first PDCCH (e.g., DCI) may be addressed to theMsgB RNTI (or RA-RNTI), e.g., if the wireless device transmit the RRCrequest message (e.g., CCCH SDU). The wireless device may receive, basedon the DL assignment, the PDSCH. The PDSCH may comprise the MsgB, aresponse of the MsgA. The wireless device may determine the two-step RAprocedure is successfully complete in response to receiving the MsgB.The wireless device may determine the two-step RA procedure issuccessfully complete in response to receiving the first PDCCH (e.g.,indicating the PDSCH comprising the MsgB corresponding to the MsgA). Thewireless device may determine the two-step RA procedure is successfullycomplete in response to receiving the PDSCH (e.g., comprising the MsgBcorresponding to the MsgA). The wireless device may identify the MsgB asthe response of the MsgA from the PDSCH (e.g., a MAC PDU) based onexample embodiments described in this specification (e.g., based on anRAPID and/or the contention resolution identifier). The wireless devicemay monitor a downlink control channel after or in response to thetwo-step RA procedure being successfully complete. The wireless devicemay receive a second PDCCH via the downlink control channel after or inresponse to the two-step RA procedure being successfully complete. Thesecond PDCCH may be a PDCCH addressed to the C-RNTI and/or firstlyreceived after or in response to the two-step RA procedure beingsuccessfully complete. The second PDCCH may be a PDCCH indicating a DLor UL transmission (e.g., a new DL or UL transmission) addressed to theC-RNTI. For example, the wireless device receives no PDCCH addressed tothe C-RNTI between a reception of the PDSCH and a reception of thesecond PDCCH. For example, the wireless device receives, from a basestation, the C-RNTI before transmitting the MsgA (e.g., the wirelessdevice is in an RRC connected state). For example, the wireless devicereceives, from a base station, the C-RNTI via the MsgB.

In FIG. 30A, the wireless device may start an active time with a firsttime offset in response to transmitting the MsgA (or transport block ofthe MsgA). The first time offset may be predefined as a first value(e.g., zero). For example, the first time offset may be a referencesymbol (e.g., first symbol or firstly located symbol in time) of aCORESET. For example, the CORESET is the earliest CORESET that is atleast one or more symbols (e.g., at least one symbol) after a lastsymbol of a preamble transmission occasion of the preamble. For example,the CORESET is the earliest CORESET that is at least one or more symbols(e.g., at least one symbol) after a last symbol of a transport block(and/or MsgA) transmission occasion of the transport block (and/orMsgA). For example, the wireless device may determine, as the activetime, a time until the wireless device receive the first PDCCH. Forexample, the wireless device may determine, as the active time, a timeuntil the wireless device receive the PDSCH. For example, the wirelessdevice may determine, as the active time, a time until the wirelessdevice receive the second PDCCH. For example, the wireless device maydetermine, as the active time, a time until the msgB RAR window expiresor stops. The wireless device may stop the msgB RAR window in responseto receiving the first PDCCH. The wireless device may stop the msgB RARwindow in response to receiving the PDSCH.

FIG. 30A may be an example for a wireless device transmitting a C-RNTI(e.g., C-RNTI MAC CE) via the transport block of the MsgA. For example,the wireless device monitors, during a msgB RAR window, a downlinkcontrol channel. The wireless device may start the msgB RAR window inresponse to transmitting the MsgA. The wireless device may receive, viathe downlink control channel, a first PDCCH addressed to the C-RNTI. Thefirst PDCCH may comprise a DL assignment indicating a reception ofPDSCH. The PDSCH may comprise at least one of: a TA command, a UL grant,a DL assignment). The wireless device may determine the two-step RAprocedure is successfully complete (and/or a contention resolution issuccessful) based on receiving the first PDCCH addressed to the C-RNTI.The wireless device may determine the two-step RA procedure issuccessfully complete (and/or a contention resolution is successful)based on receiving (and/or successfully decoding) the PDSCH based on aDL assignment of the first PDCCH. The wireless device may determine tostart an active time in response to transmitting the Msg A (and/ortransport block of the MsgA). The wireless device may stop the activetime in response to receiving the first PDCCH. For example, a durationof the active time comprises a second duration between a first timetransport block is transmitted and a second time the first PDCCH isreceived. The wireless device may determine to start an active time inresponse to transmitting the Msg A (and/or transport block of the MsgA).The wireless device may stop the active time in response to determiningthe two-step RA procedure being successfully compete (and/or thecontention resolution is successful). For example, a duration of theactive time comprises a second duration between a first time transportblock is transmitted and a second time the PDSCH is received. Thewireless device may determine to start an active time in response totransmitting the Msg A (and/or transport block of the MsgA). Thewireless device may stop the active time in response to receiving thesecond PDCCH. For example, a duration of the active time comprises asecond duration between a first time the transport block is transmittedand a second time the second PDCCH is received. The msgB RAR window maystop based on receiving the first PDCCH addressed to the C-RNTI. ThemsgB RAR window may stop based on receiving the PDSCH. For example, thewireless device receives the PDSCH based on the DL assignment of thefirst PDCCH addressed to the C-RNTI.

FIG. 30B is an example of a DRX operation. The wireless device mayinitiate a two-step RA procedure. The two-step RA procedure may be acontention-based two-step RA procedure. For example, for thecontention-based two-step RA procedure, a preamble transmitted by thewireless device via MsgA is selected by an MAC layer of the wirelessdevice among the one or more preambles assigned (or configured orallocated) for the contention-based two-step RA procedure. The two-stepRA procedure may be a contention-free two-step RA procedure. Forexample, for the contention-free two-step RA procedure, a preambletransmitted by the wireless device via MsgA is not selected by an MAClayer of the wireless device among the one or more preambles assigned(or configured or allocated) for the contention-based two-step RAprocedure. The wireless device may transmit a preamble and a transportblock as a transmission of an MsgA. The wireless device may start tomonitor a downlink control channel for a response of the MsgA. Thewireless device may monitor the downlink control channel based on aC-RNTI, e.g., if the transport block comprises the C-RNTI (e.g., C-RNTIMAC CE). The wireless device may monitor the downlink control channelbased on a msgB RNTI (or RA-RNTI), e.g., if the transport blockcomprises an RRC request message (e.g., CCCH SDU) (and/or the transportblock does not comprise the C-RNTI (e.g., C-RNTI MAC CE)). The wirelessdevice may receive a first PDCCH via the downlink control channel. Thewireless device may receive the first PDCCH during a msgB RAR windowstarting in response to transmitting the MsgA (or transport block of theMsgA). The first PDCCH (e.g., DCI) may indicate a DL assignment forreceiving a PDSCH (e.g., MsgB). The first PDCCH (e.g., DCI) may beaddressed to the C-RNTI, e.g., if the wireless device transmits theC-RNTI via the MsgA. The first PDCCH (e.g., DCI) may be addressed to theMsgB RNTI (or RA-RNTI), e.g., if the wireless device transmit the RRCrequest message (e.g., CCCH SDU). The wireless device may receive, basedon the DL assignment, the PDSCH. The PDSCH may comprise the MsgB, aresponse of the MsgA. The wireless device may determine the two-step RAprocedure is successfully complete in response to receiving the MsgB.The wireless device may determine the two-step RA procedure issuccessfully complete in response to receiving the first PDCCH (e.g.,indicating the PDSCH comprising the MsgB corresponding to the MsgA). Thewireless device may determine the two-step RA procedure is successfullycomplete in response to receiving the PDSCH (e.g., comprising the MsgBcorresponding to the MsgA). The wireless device may identify the MsgB asthe response of the MsgA from the PDSCH (e.g., a MAC PDU) based onexample embodiments described in this specification (e.g., based on anRAPID and/or the contention resolution identifier). The wireless devicemay monitor a downlink control channel after or in response to thetwo-step RA procedure being successfully complete. The wireless devicemay receive a second PDCCH via the downlink control channel after or inresponse to the two-step RA procedure being successfully complete. Thesecond PDCCH may be a PDCCH addressed to the C-RNTI and/or firstlyreceived after or in response to the two-step RA procedure beingsuccessfully complete. The second PDCCH may be a PDCCH indicating a DLor UL transmission (e.g., a new DL or UL transmission) addressed to theC-RNTI. For example, the wireless device receives no PDCCH addressed tothe C-RNTI between a reception of the PDSCH and a reception of thesecond PDCCH. For example, the wireless device receives, from a basestation, the C-RNTI before transmitting the MsgA (e.g., the wirelessdevice is in an RRC connected state). For example, the wireless devicereceives, from a base station, the MsgB comprising the C-RNTI (orTC-RNTI promoted to C-RNTI in response to the two-step RA procedurebeing successfully complete).

In FIG. 30B, a wireless device may start an active time with a firsttime offset in response to receiving the first PDCCH and stop the activetime in response to receiving the PDSCH. The first time offset may bepredefined as a first value (e.g., zero). For example, the first timeoffset may be a reference symbol (e.g., first symbol or firstly locatedsymbol in time) of a CORESET. For example, the CORESET is the earliestCORESET that is at least one or more symbols (e.g., at least one symbol)after receiving the first PDCCH. For example, the CORESET is theearliest CORESET comprising one or more symbols where the first PDCCH isreceive.

In FIG. 30B, a wireless device may start an active time with a firsttime offset in response to receiving the first PDCCH. The wirelessdevice may determine the active time until the wireless device receivesthe second PDCCH (and/or may stop the active time in response toreceiving the second PDCCH). The first time offset may be predefined asa first value (e.g., zero). For example, the first time offset may be areference symbol (e.g., first symbol or firstly located symbol in time)of a CORESET. For example, the CORESET is the earliest CORESET that isat least one or more symbols (e.g., at least one symbol) after receivingthe first PDCCH. For example, the CORESET is the earliest CORESETcomprising one or more symbols where the first PDCCH is receive.

In FIG. 30B, a wireless device may start an active time with a firsttime offset in response to receiving the PDSCH. The wireless device maydetermine, as the active time, a time until the wireless device receivethe second PDCCH. The first time offset may be predefined as a firstvalue (e.g., zero). For example, the first time offset may be areference symbol (e.g., first symbol or firstly located symbol in time)of a CORESET. For example, the CORESET is the earliest CORESET that isat least one or more symbols (e.g., at least one symbol) after receivingthe first PDCCH. For example, the CORESET is the earliest CORESETcomprising one or more symbols where the first PDCCH is receive.

FIG. 30B may be an example for a wireless device transmitting a C-RNTI(e.g., C-RNTI MAC CE) via the transport block of the MsgA. For example,the wireless device monitors, during a msgB RAR window, a downlinkcontrol channel. For example, the wireless device may start the msgB RARwindow in response to transmitting the MsgA. the wireless device mayreceive, via the downlink control channel, a first PDCCH addressed tothe C-RNTI. The first PDCCH may comprise a DL assignment indicating areception of PDSCH. The PDSCH may comprise at least one of: a TAcommand, a UL grant, a DL assignment). The wireless device may determinethe two-step RA procedure is successfully complete (and/or a contentionresolution is successful) based on receiving the first PDCCH addressedto the C-RNTI. The wireless device may determine the two-step RAprocedure is successfully complete (and/or a contention resolution issuccessful) based on receiving (and/or successfully decoding) the PDSCHbased on a DL assignment of the first PDCCH. In FIG. 30B, the wirelessdevice may determine to start an active time in response to receivingthe first PDCCH. The wireless device may stop the active time inresponse to receiving the PDSCH. For example, a duration of the activetime comprises a second duration between a first time the first PDCCH isreceived and a second time the PDSCH is received. In FIG. 30B, thewireless device may determine to start an active time in response todetermining the two-step RA procedure being successfully compete (and/orthe contention resolution is successful) and stop the active time inresponse to receiving the second PDCCH. The wireless device maydetermine the two-step RA procedure being successfully compete (and/orthe contention resolution is successful) in response to receiving thefirst PDCCH (e.g., addressed to the C-RNTI). For example, the wirelessdevice starts an active time in response to receiving the first PDCCH(e.g., addressed to the C-RNTI). The wireless device may stope theactive time in response to receiving the second PDCCH. In this case, aduration of the active time comprises a second duration between a firstreception time of the first PDCCH and a second reception time of thesecond PDCCH. In FIG. 30B, the wireless device may determine to start anactive time in response to determining the two-step RA procedure beingsuccessfully compete (and/or the contention resolution is successful)and stop the active time in response to receiving the second PDCCH. Thewireless device may determine the two-step RA procedure beingsuccessfully compete (and/or the contention resolution is successful) inresponse to receiving the PDSCH (e.g., and/or in response tosuccessfully decoding the PDSCH). For example, the wireless devicestarts an active time in response to receiving the PDSCH (e.g., and/orin response to successfully decoding the PDSCH). The wireless device maystop the active time in response to receiving the second PDCCH. In thiscase, a duration of the active time comprises a second duration betweena first reception time of the PDSCH and a second reception time of thesecond PDCCH. The msgB RAR window may stop based on receiving the firstPDCCH addressed to the C-RNTI. The msgB RAR window may stop based onreceiving the PDSCH. For example, the wireless device receives the PDSCHbased on the DL assignment of the first PDCCH addressed to the C-RNTI.

According to an example embodiment, a wireless device may determine anactive time during a two-step RA procedure, independent of a msgB RARwindow. For example, the two-step RA procedure is a contention-basedtwo-step RA procedure. For example, the two-step RA procedure is acontention-free two-step RA procedure. The wireless device may start aduration of an active time after or in response to transmitting MsgA(e.g., transport block of MsgA). The MsgA (e.g., transport block ofMsgA) may comprise an RRC request message. The RRC request message maybe at least one of: RRC (re)establishment request, RRC setup request,and/or RRC resume request. The MsgA (e.g., transport block of MsgA) maycomprise a wireless device identifier for a contention resolution. TheMsgA (e.g., transport block of MsgA) may comprise a C-RNTI (e.g., C-RNTIMAC CE). A response of the MsgA may be an MsgB1 (e.g., an success RARcomprising at least one of TA command, UL grant, DL assignment, and/or acontention resolution identifier) and an MsgB2 (e.g., an RRC messagecomprising at least one of RRC (re)establishment, RRC setup, and/or RRCresume). The wireless device may receive a PDSCH comprising the MsgB1and the MsgB2. The wireless device may receive the MsgB1 and the MsgB2via different PDSCHs. For example, the wireless device receives theMsgB1 via a first PDSCH (e.g., comprising the MsgB1) and receives theMsgB2 via a second PDSCH (e.g., comprising the MsgB2).

According to an example embodiment, a wireless device may determine aduration of an active time based on whether the wireless device receivethe MsgB1 and MsgB2 in the same PDSCH or not. In an example, MsgB inFIG. 30A and FIG. 30B comprises the MsgB1 and MsgB2. For example, FIG.30A and FIG. 30B are examples that the wireless device receives MsgB1and MsgB2 as the MsgB in the same PDSCH (e.g., the PDSCH in FIG. 30B).

According to an example embodiment, a wireless device may identify,based on an explicit or implicit indication in an MAC PDU of a PDSCH.For example, the wireless device transmits an MsgA and receives thePDSCH. The MAC PDU of the PDSCH may comprise one or more responses. Forexample, one of the one or more responses may be a success RAR (e.g.,MsgB1). For example, one of the one or more responses may be an RRCmessage (e.g., MsgB2). For example, one of the one or more responses maybe a fallback RAR. For example, the one or more responses may comprise aresponse comprising a success RAR (e.g., MsgB1) and an RRC message(e.g., MsgB2). The MAC PDU may comprise a first indication indicating(e.g., a first field indicating) whether the success RAR (e.g., MsgB1)and the RRC message (e.g., MsgB2) are in the same response. For example,the MAC PDU comprises a MACsubPDU. The MACsubPDU may comprise thesuccess RAR (e.g., MsgB1) and/or the RRC message (e.g., MsgB2). Forexample, the MACsubPDU comprise the first indication (e.g., the firstfield). The first indication (or the first field) may be referred to asa first MsgB2 indication in this specification. The wireless device maydetermine whether the success RAR (e.g., MsgB1) and the RRC message(e.g., MsgB2) are in the same response (e.g., MACsubPDU). For example,the one or more responses may comprise a single response comprising asuccess RAR (e.g., MsgB1) and an RRC message (e.g., MsgB2). The one ormore responses may comprise a single response in response to the singleresponse the success RAR (e.g., MsgB1) and the RRC message (e.g.,MsgB2). The MAC PDU may comprise a second indication indicating (e.g., asecond field indicating) whether the success RAR (e.g., MsgB1) and theRRC message (e.g., MsgB2) are in the same response. The secondindication (or the second field) may be referred to as a second MsgB2indication in this specification. The second indication (e.g., thesecond field) may indicate whether the one or more responses comprises asingle response (e.g., comprising success RAR (e.g., MsgB1) and the RRCmessage (e.g., MsgB2)) or not. For example, if the second indication (orthe second field) indicates the one or more responses comprises a singleresponse, and/or if an RAPID field value in the response is not matchedto an identifier of a preamble that the wireless device transmits viathe MsgA, the wireless device may monitor (e.g., return to monitor,and/or keep monitoring) a downlink control channel. For example, if thesecond indication (or the second field) indicates the one or moreresponses comprises a single response, and/or if an RAPID field value inthe response is matched to an identifier of a preamble that the wirelessdevice transmits via the MsgA, the wireless device may continue to parsethe response. For example, the wireless device may determine whether acontention resolution identifier (e.g., indicated by the MsgB1 or MsgB2)is matched to a wireless device identifier (e.g., transmitted via atransport block of the MsgA).

FIG. 31 is an example of a DRX operation. The wireless device mayinitiate a two-step RA procedure performing. The two-step RA proceduremay be a contention-based two-step RA procedure. For example, for thecontention-based two-step RA procedure, a preamble transmitted by thewireless device via MsgA is selected by an MAC layer of the wirelessdevice among the one or more preambles assigned (or configured orallocated) for the contention-based two-step RA procedure. The two-stepRA procedure may be a contention-free two-step RA procedure. Forexample, for the contention-free two-step RA procedure, a preambletransmitted by the wireless device via MsgA is not selected by an MAClayer of the wireless device among the one or more preambles assigned(or configured or allocated) for the contention-based two-step RAprocedure. The wireless device may transmit a preamble and a transportblock as a transmission of an MsgA. The wireless device may start tomonitor a downlink control channel for a response of the MsgA. Thewireless device may monitor the downlink control channel based on aC-RNTI, e.g., if the transport block comprises the C-RNTI (e.g., C-RNTIMAC CE). The wireless device may monitor the downlink control channelbased on a msgB RNTI (or RA-RNTI), e.g., if the transport blockcomprises an RRC request message (e.g., CCCH SDU) (and/or the transportblock does not comprise the C-RNTI (e.g., C-RNTI MAC CE)). The wirelessdevice may receive a first PDCCH via the downlink control channel. Thewireless device may receive the first PDCCH during a msgB RAR windowstarting in response to transmitting the MsgA (or transport block of theMsgA). The first PDCCH (e.g., DCI) may indicate a first DL assignmentfor receiving a first PDSCH (e.g., MsgB1). The first PDCCH (e.g., DCI)may be addressed to the C-RNTI, e.g., if the wireless device transmitsthe C-RNTI via the MsgA. The first PDCCH (e.g., DCI) may be addressed tothe msgB RNTI (or RA-RNTI), e.g., if the wireless device transmit theRRC request message (e.g., CCCH SDU). The wireless device may receive,based on the first DL assignment, the first PDSCH. The first PDSCH maycomprise the MsgB1, a response of the MsgA. For example, the MsgB1comprise at least one of: a TA command, a UL grant, a second DLassignment, and/or a contention resolution identifier. The wirelessdevice may determine the two-step RA procedure is successfully completein response to receiving the MsgB1. The wireless device may determinethe two-step RA procedure is successfully complete in response toreceiving the first PDSCH (e.g., comprising the MsgB1). The wirelessdevice may identify the MsgB1 as the response of the MsgA from the firstPDSCH (e.g., a MAC PDU) based on example embodiments described in thisspecification (e.g., based on an RAPID and/or the contention resolutionidentifier). For example, the first PDSCH (e.g., comprising the MsgB1)comprises an indicator (e.g., the first MsgB2 indication and/or thesecond MsgB2 indication). The wireless device determines, based on theindicator, the MsgB2 is not in the first PDSCH. The wireless device maymonitor a downlink control channel after or in response to receiving theMsgB1 based on determining the MsgB2 is not in the first PDSCH and/orthe MsgB1 is a response of the MsgA. The wireless device may monitor thedownlink control channel based on a particular RNTI. The particular RNTImay be a C-RNTI or TC-RNTI. The MsgB1 may comprise the particular RNTI.The wireless device may receive a second PDCCH via the downlink controlchannel after or in response to receiving the first PDSCH (e.g.,comprising the MsgB1). The second PDCCH may comprise a third DLassignment. The wireless device may receive, based on the third DLassignment, the second PDSCH. For example, the second PDCCH is a PDCCHaddressed to the C-RNTI and/or firstly received after or in response tothe two-step RA procedure being successfully complete. For example, thesecond PDCCH is a PDCCH addressed to the C-RNTI and/or firstly receivedafter or in response to receiving the first PDSCH. The second PDCCH maybe a PDCCH indicating a DL or UL transmission (e.g., a new DL or ULtransmission) addressed to the C-RNTI. For example, the wireless devicereceives no PDCCH addressed to the C-RNTI between a reception of thefirst PDSCH and a reception of the second PDCCH. The wireless device mayreceive, based on the third DL assignment, the second PDSCH. The secondPDSCH may comprise the RRC message. For example, the RRC message may beone of RRC (re)establishment message, RRC setup message, and/or RRCresume message. The wireless device may determine the two-step RAprocedure is successfully complete in response to receiving the MsgB2.The wireless device may determine the two-step RA procedure issuccessfully complete in response to receiving the second PDSCH (e.g.,comprising the MsgB2). The wireless device may stop the msgB RAR windowin response to receiving the first PDSCH. The wireless device may stopthe msgB RAR window in response to receiving the second PDSCH.

In FIG. 31 , a wireless device may start an active time with a firsttime offset in response to transmitting the MsgA and stop the activetime in response to receiving the first PDSCH. For example, a durationof the active time comprises a second duration between a first time theMsgA is transmitted with the first time offset and a second time thefirst PDSCH is received. The first time offset may be predefined as afirst value (e.g., zero). For example, the first time offset may be areference symbol (e.g., first symbol or firstly located symbol in time)of a CORESET. For example, the CORESET is the earliest CORESET that isat least one or more symbols (e.g., at least one symbol) after a lastsymbol of a preamble transmission occasion of the preamble. For example,the CORESET is the earliest CORESET that is at least one or more symbols(e.g., at least one symbol) after a last symbol of a transport block(and/or MsgA) transmission occasion of the transport block (and/orMsgA).

In FIG. 31 , a wireless device may start an active time with a firsttime offset in response to transmitting the MsgA. The wireless devicemay determine the active time until the wireless device receives thesecond PDCCH (and/or may stop the active time in response to receivingthe second PDCCH). For example, a duration of the active time comprisesa second duration between a first time the MsgA is transmitted the firsttime offset and a second time the second PDCCH is received. The firsttime offset may be predefined as a first value (e.g., zero). Forexample, the first time offset may be a reference symbol (e.g., firstsymbol or firstly located symbol in time) of a CORESET. For example, theCORESET is the earliest CORESET that is at least one or more symbols(e.g., at least one symbol) after a last symbol of a preambletransmission occasion of the preamble. For example, the CORESET is theearliest CORESET that is at least one or more symbols (e.g., at leastone symbol) after a last symbol of a transport block (and/or MsgA)transmission occasion of the transport block (and/or MsgA). The wirelessdevice may (re)start, based on receiving the second PDCCH and/or basedon a DRX operation described in the specification, one or more firsttimers and/or stop one or more second timers. For example, the one ormore first timers comprise drx-HARQ-RTT-TimerDL (e.g., the second PDCCHcomprise a DL assignment). For example, the one or more first timerscomprise drx-HARQ-RTT-TimerUL (e.g., the second PDCCH comprise a ULgrant). For example, the one or more first timers comprisedrx-InactivityTimer (e.g., the second PDCCH indicating a newtransmission (DL or UL). The one or more second timers comprisedrx-RetransmissionTimerDL (e.g., the second PDCCH comprise a DLassignment). The one or more second timers comprisedrx-RetransmissionTimerUL (e.g., the second PDCCH comprise a UL grant).

In FIG. 31 , a wireless device may start an active time with a firsttime offset in response to transmitting the MsgA. The wireless devicemay determine, as the active time, a time until the wireless devicereceive the second PDSCH (and/or may stop the active time in response toreceiving the second PDSCH). For example, a duration of the active timecomprises a second duration between a first time the MsgA is transmittedthe first time offset and a second time the second PDSCH is received.The first time offset may be predefined as a first value (e.g., zero).For example, the first time offset may be a reference symbol (e.g.,first symbol or firstly located symbol in time) of a CORESET. Forexample, the CORESET is the earliest CORESET that is at least one ormore symbols (e.g., at least one symbol) after a last symbol of apreamble transmission occasion of the preamble. For example, the CORESETis the earliest CORESET that is at least one or more symbols (e.g., atleast one symbol) after a last symbol of a transport block (and/or MsgA)transmission occasion of the transport block (and/or MsgA).

FIG. 32 is an example of a DRX operation. The wireless device mayinitiate a two-step RA procedure performing. The two-step RA proceduremay be a contention-based two-step RA procedure. For example, for thecontention-based two-step RA procedure, a preamble transmitted by thewireless device via MsgA is selected by an MAC layer of the wirelessdevice among the one or more preambles assigned (or configured orallocated) for the contention-based two-step RA procedure. The two-stepRA procedure may be a contention-free two-step RA procedure. Forexample, for the contention-free two-step RA procedure, a preambletransmitted by the wireless device via MsgA is not selected by an MAClayer of the wireless device among the one or more preambles assigned(or configured or allocated) for the contention-based two-step RAprocedure. The wireless device may transmit a preamble and a transportblock as a transmission of an MsgA. The wireless device may start tomonitor a downlink control channel for a response of the MsgA. Thewireless device may monitor the downlink control channel based on aC-RNTI, e.g., if the transport block comprises the C-RNTI (e.g., C-RNTIMAC CE). The wireless device may monitor the downlink control channelbased on a msgB RNTI (or RA-RNTI), e.g., if the transport blockcomprises an RRC request message (e.g., CCCH SDU) (and/or the transportblock does not comprise the C-RNTI (e.g., C-RNTI MAC CE)). The wirelessdevice may receive a first PDCCH via the downlink control channel. Thewireless device may receive the first PDCCH during a msgB RAR windowstarting in response to transmitting the MsgA (or transport block of theMsgA). The first PDCCH (e.g., DCI) may indicate a first DL assignmentfor receiving a first PDSCH (e.g., MsgB1). The first PDCCH (e.g., DCI)may be addressed to the C-RNTI, e.g., if the wireless device transmitsthe C-RNTI via the MsgA. The first PDCCH (e.g., DCI) may be addressed tothe msgB RNTI (or RA-RNTI), e.g., if the wireless device transmit theRRC request message (e.g., CCCH SDU). The wireless device may receive,based on the first DL assignment, the first PDSCH. The first PDSCH maycomprise the MsgB1, a response of the MsgA. For example, the MsgB1comprise at least one of: a TA command, a UL grant, a second DLassignment, and/or a contention resolution identifier. The wirelessdevice may determine the two-step RA procedure is successfully completein response to receiving the MsgB1. The wireless device may determinethe two-step RA procedure is successfully complete in response toreceiving the first PDSCH (e.g., comprising the MsgB1). The wirelessdevice may identify the MsgB1 as the response of the MsgA from the firstPDSCH (e.g., a MAC PDU) based on example embodiments described in thisspecification (e.g., based on an RAPID and/or the contention resolutionidentifier). For example, the first PDSCH (e.g., comprising the MsgB1)comprises an indicator (e.g., the first MsgB2 indication and/or thesecond MsgB2 indication). The wireless device determines, based on theindicator, the MsgB2 is not in the first PDSCH. The wireless device maymonitor a downlink control channel after or in response to receiving theMsgB1 based on determining the MsgB2 is not in the first PDSCH and/orthe MsgB1 is a response of the MsgA. The wireless device may monitor thedownlink control channel based on a particular RNTI. The particular RNTImay be a C-RNTI or TC-RNTI. The MsgB1 may comprise the particular RNTI.The wireless device may receive a second PDCCH via the downlink controlchannel after or in response to receiving the first PDSCH (e.g.,comprising the MsgB1). The second PDCCH may comprise a third DLassignment. The wireless device may receive, based on the third DLassignment, the second PDSCH. For example, the second PDCCH is a PDCCHaddressed to the C-RNTI and/or firstly received after or in response tothe two-step RA procedure being successfully complete. For example, thesecond PDCCH is a PDCCH addressed to the C-RNTI and/or firstly receivedafter or in response to receiving the first PDSCH. The second PDCCH maybe a PDCCH indicating a DL or UL transmission (e.g., a new DL or ULtransmission) addressed to the C-RNTI. For example, the wireless devicereceives no PDCCH addressed to the C-RNTI between a reception of thefirst PDSCH and a reception of the second PDCCH. The wireless device mayreceive, based on the third DL assignment, the second PDSCH. The secondPDSCH may comprise the RRC message. For example, the RRC message may beone of RRC (re)establishment message, RRC setup message, and/or RRCresume message. The wireless device may determine the two-step RAprocedure is successfully complete in response to receiving the MsgB2.The wireless device may determine the two-step RA procedure issuccessfully complete in response to receiving the second PDSCH (e.g.,comprising the MsgB2). The wireless device may stop the msgB RAR windowin response to receiving the first PDSCH. The wireless device may stopthe msgB RAR window in response to receiving the second PDSCH.

In FIG. 32 , a wireless device may start an active time with a firsttime offset in response to receiving the first PDCCH. The wirelessdevice may stop the active time in response to receiving the secondPDCCH. For example, a duration of the active time comprises a secondduration between a first time first PDCCH is received with the firsttime offset and a second time the second PDCCH is received. For example,the first time offset may be predefined as a first value (e.g., zero).For example, the first time offset may be a reference symbol (e.g.,first symbol or firstly located symbol in time) of a CORESET. Forexample, the CORESET is the earliest CORESET that is at least one ormore symbols (e.g., at least one symbol) after receiving the firstPDCCH. For example, the CORESET is the earliest CORESET comprising oneor more symbols where the first PDCCH is receive. The wireless devicemay (re)start, based on receiving the second PDCCH and/or based on a DRXoperation described in the specification, one or more first timersand/or stop one or more second timers. For example, the one or morefirst timers comprise drx-HARQ-RTT-TimerDL (e.g., the second PDCCHcomprise a DL assignment). For example, the one or more first timerscomprise drx-HARQ-RTT-TimerUL (e.g., the second PDCCH comprise a ULgrant). For example, the one or more first timers comprisedrx-InactivityTimer (e.g., the second PDCCH indicating a newtransmission (DL or UL). The one or more second timers comprisedrx-RetransmissionTimerDL (e.g., the second PDCCH comprise a DLassignment). The one or more second timers comprisedrx-RetransmissionTimerUL (e.g., the second PDCCH comprise a UL grant).

In FIG. 32 , a wireless device may start an active time with a firsttime offset in response to receiving the first PDCCH. The wirelessdevice may determine the active time until the wireless device receivesthe second PDSCH (and/or may stop the active time in response toreceiving the second PDSCH). For example, a duration of the active timecomprises a second duration between a first time first PDCCH is receivedwith the first time offset and a second time the second PDSCH isreceived. The first time offset may be predefined as a first value(e.g., zero). For example, the first time offset may be a referencesymbol (e.g., first symbol or firstly located symbol in time) of aCORESET. For example, the CORESET is the earliest CORESET that is atleast one or more symbols (e.g., at least one symbol) after receivingthe first PDCCH. For example, the CORESET is the earliest CORESETcomprising one or more symbols where the first PDCCH is receive.

In FIG. 32 , a wireless device may start an active time in response toreceiving the first PDSCH. The wireless device may determine, as theactive time, a time until the wireless device receive the second PDCCH.For example, a duration of the active time comprises a second durationbetween a first time first PDSCH is received and a second time thesecond PDCCH is received. The wireless device may (re)start, based onreceiving the second PDCCH and/or based on a DRX operation described inthe specification, one or more first timers and/or stop one or moresecond timers. For example, the one or more first timers comprisedrx-HARQ-RTT-TimerDL (e.g., the second PDCCH comprise a DL assignment).For example, the one or more first timers comprise drx-HARQ-RTT-TimerUL(e.g., the second PDCCH comprise a UL grant). For example, the one ormore first timers comprise drx-InactivityTimer (e.g., the second PDCCHindicating a new transmission (DL or UL). The one or more second timerscomprise drx-RetransmissionTimerDL (e.g., the second PDCCH comprise a DLassignment). The one or more second timers comprisedrx-RetransmissionTimerUL (e.g., the second PDCCH comprise a UL grant).

In FIG. 32 , a wireless device may start an active time in response toreceiving the first PDSCH. The wireless device may determine, as theactive time, a time until the wireless device receive the second PDSCH.For example, a duration of the active time comprises a second durationbetween a first time first PDSCH is received and a second time thesecond PDSCH is received. In FIG. 32 , a wireless device may start anactive time in response to receiving the second PDCCH. The wirelessdevice may determine, as the active time, a time until the wirelessdevice receive the second PDSCH. For example, a duration of the activetime comprises a second duration between a first time second PDCCH isreceived with and a second time the second PDSCH is received.

According to an example embodiment, a wireless device may determine anactive time during a two-step RA procedure, independent of a msgB RARwindow. For example, the two-step RA procedure is a contention-basedtwo-step RA procedure. For example, the two-step RA procedure is acontention-free two-step RA procedure. The wireless device may start aduration of an active time after or in response to transmitting MsgA(e.g., transport block of MsgA). The MsgA (e.g., transport block ofMsgA) may comprise an RRC request message. The RRC request message maybe at least one of: RRC (re)establishment request, RRC setup request,and/or RRC resume request. The MsgA (e.g., transport block of MsgA) maycomprise a wireless device identifier for a contention resolution. TheMsgA (e.g., transport block of MsgA) may comprise a C-RNTI (e.g., C-RNTIMAC CE). A response of the MsgA may be an MsgB1 (e.g., an success RARcomprising at least one of TA command, UL grant, DL assignment, and/or acontention resolution identifier) and an MsgB2 (e.g., an RRC messagecomprising at least one of RRC (re)establishment, RRC setup, and/or RRCresume). The wireless device may receive a PDSCH comprising the MsgB1and the MsgB2. The wireless device may receive the MsgB1 and the MsgB2via different PDSCHs. For example, the wireless device receives theMsgB1 via a first PDSCH (e.g., comprising the MsgB1). The first PDSCHmay comprise a DL assignment. The wireless device may receive a secondPDSCH (e.g., comprising the MsgB2) based on the DL assignment.

According to an example embodiment, a wireless device may determine aduration of an active time based on whether the wireless device receivethe MsgB1 and MsgB2 in the same PDSCH or not. In an example, MsgB inFIG. 30A and FIG. 30B comprises the MsgB1 and MsgB2. For example, FIG.30A and FIG. 30B are examples that the wireless device receives MsgB1and MsgB2 as the MsgB in the same PDSCH (e.g., the PDSCH in FIG. 30B).

According to an example embodiment, a wireless device may identify,based on an explicit or implicit indication in an MAC PDU of a PDSCH.For example, the wireless device transmits an MsgA and receives thePDSCH. The MAC PDU of the PDSCH may comprise one or more responses. Forexample, one of the one or more responses may be a success RAR (e.g.,MsgB1). For example, one of the one or more responses may be an RRCmessage (e.g., MsgB2). For example, one of the one or more responses maybe a fallback RAR. For example, the one or more responses may comprise aresponse comprising a success RAR (e.g., MsgB1) and an RRC message(e.g., MsgB2). The MAC PDU may comprise a first indication indicating(e.g., a first field indicating) whether the success RAR (e.g., MsgB1)and the RRC message (e.g., MsgB2) are in the same response. For example,the MAC PDU comprises a MACsubPDU. The MACsubPDU may comprise thesuccess RAR (e.g., MsgB1) and/or the RRC message (e.g., MsgB2). Forexample, the MACsubPDU comprise the first indication (e.g., the firstfield). The first indication (or the first field) may be referred to asa first MsgB2 indication in this specification. The wireless device maydetermine whether the success RAR (e.g., MsgB1) and the RRC message(e.g., MsgB2) are in the same response (e.g., MACsubPDU). For example,the one or more responses may comprise a single response comprising asuccess RAR (e.g., MsgB1) and an RRC message (e.g., MsgB2). The one ormore responses may comprise a single response in response to the singleresponse the success RAR (e.g., MsgB1) and the RRC message (e.g.,MsgB2). The MAC PDU may comprise a second indication indicating (e.g., asecond field indicating) whether the success RAR (e.g., MsgB1) and theRRC message (e.g., MsgB2) are in the same response. The secondindication (or the second field) may be referred to as a second MsgB2indication in this specification. The second indication (e.g., thesecond field) may indicate whether the one or more responses comprises asingle response (e.g., comprising success RAR (e.g., MsgB1) and the RRCmessage (e.g., MsgB2)) or not. For example, if the second indication (orthe second field) indicates the one or more responses comprises a singleresponse, and/or if an RAPID field value in the response is not matchedto an identifier of a preamble that the wireless device transmits viathe MsgA, the wireless device may attempt to receive the RRC message(e.g., MsgB2). In this case the MsgB1 may comprise a DL assignment. TheDL assignment may indicate a DL scheduling information of a secondPDSCH. The second PDSCH may comprise the RRC message (e.g., MsgB2). Forexample, if the second indication (or the second field) indicates theone or more responses comprises a single response, and/or if an RAPIDfield value in the response is matched to an identifier of a preamblethat the wireless device transmits via the MsgA, the wireless device maycontinue to parse the response. For example, the wireless device maydetermine whether a contention resolution identifier (e.g., indicated bythe MsgB1 or MsgB2) is matched to a wireless device identifier (e.g.,transmitted via a transport block of the MsgA).

FIG. 33 is an example of a DRX operation. The wireless device mayinitiate a two-step RA procedure performing. The two-step RA proceduremay be a contention-based two-step RA procedure. For example, for thecontention-based two-step RA procedure, a preamble transmitted by thewireless device via MsgA is selected by an MAC layer of the wirelessdevice among the one or more preambles assigned (or configured orallocated) for the contention-based two-step RA procedure. The two-stepRA procedure may be a contention-free two-step RA procedure. Forexample, for the contention-free two-step RA procedure, a preambletransmitted by the wireless device via MsgA is not selected by an MAClayer of the wireless device among the one or more preambles assigned(or configured or allocated) for the contention-based two-step RAprocedure. The wireless device may transmit a preamble and a transportblock as a transmission of an MsgA. The wireless device may start tomonitor a downlink control channel for a response of the MsgA. Thewireless device may monitor the downlink control channel based on aC-RNTI, e.g., if the transport block comprises the C-RNTI (e.g., C-RNTIMAC CE). The wireless device may monitor the downlink control channelbased on a msgB RNTI (or RA-RNTI), e.g., if the transport blockcomprises an RRC request message (e.g., CCCH SDU) (and/or the transportblock does not comprise the C-RNTI (e.g., C-RNTI MAC CE)). The wirelessdevice may receive a first PDCCH via the downlink control channel. Thewireless device may receive the first PDCCH during a msgB RAR windowstarting in response to transmitting the MsgA (or transport block of theMsgA). The first PDCCH (e.g., DCI) may indicate a first DL assignmentfor receiving a first PDSCH (e.g., MsgB1). The first PDCCH (e.g., DCI)may be addressed to the C-RNTI, e.g., if the wireless device transmitsthe C-RNTI via the MsgA. The first PDCCH (e.g., DCI) may be addressed tothe msgB RNTI (or RA-RNTI), e.g., if the wireless device transmit theRRC request message (e.g., CCCH SDU). The wireless device may receive,based on the first DL assignment, the first PDSCH. The first PDSCH maycomprise the MsgB1, a response of the MsgA. For example, the MsgB1comprise at least one of: a TA command, a UL grant, and/or a contentionresolution identifier. The wireless device may determine the two-step RAprocedure is successfully complete in response to receiving the MsgB1.The wireless device may determine the two-step RA procedure issuccessfully complete in response to receiving the first PDSCH (e.g.,comprising the MsgB1). The wireless device may identify the MsgB1 as theresponse of the MsgA from the first PDSCH (e.g., a MAC PDU) based onexample embodiments described in this specification (e.g., based on anRAPID and/or the contention resolution identifier). For example, thefirst PDSCH (e.g., comprising the MsgB1) comprises an indicator (e.g.,the first MsgB2 indication and/or the second MsgB2 indication). Thewireless device determines, based on the indicator, the MsgB2 is not inthe first PDSCH. The MsgB2 may further comprise a second DL assignment.The second DL assignment may indicate a DL scheduling informationrequired for receiving a second PDSCH (e.g., comprising the MsgB2). Thewireless device may receive, based on the second DL assignment, thesecond PDSCH (e.g., comprising the MsgB2). The wireless device mayattempt to receive, based on the second DL assignment, the second PDSCHbased on determining that the MsgB2 is not in the first PDSCH and/or theMsgB1 is a response of the MsgA. the second DL assignment may indicateone or more DL transmission parameters, e.g., a reception timing, areceiving frequency, a size of the PDSCH, and the like. The second PDSCHmay comprise the RRC message. For example, the RRC message may be one ofRRC (re)establishment message, RRC setup message, and/or RRC resumemessage. The wireless device may determine the two-step RA procedure issuccessfully complete in response to receiving the MsgB2. The wirelessdevice may determine the two-step RA procedure is successfully completein response to receiving the second PDSCH (e.g., comprising the MsgB2).The wireless device may stop the msgB RAR window in response toreceiving the first PDSCH. The wireless device may stop the msgB RARwindow in response to receiving the second PDSCH. The wireless devicemay start to monitor a downlink control channel based on a particularRNTI, e.g., after or in response to receiving the second PDSCH (e.g.,comprising the MsgB2). The particular RNTI may be a C-RNTI or TC-RNTI.The MsgB1 may comprise the particular RNTI. The wireless device mayreceive a second PDCCH via the downlink control channel after or inresponse to receiving the second PDSCH (e.g., comprising the MsgB2). Forexample, the second PDCCH is a PDCCH addressed to the C-RNTI and/orfirstly received after or in response to receiving the first PDSCH. Forexample, the wireless device receives no PDCCH addressed to the C-RNTIbetween a reception of the first PDSCH and a reception of the secondPDCCH. For example, the second PDCCH is a PDCCH addressed to the C-RNTIand/or firstly received after or in response to receiving the secondPDSCH. For example, the wireless device receives no PDCCH addressed tothe C-RNTI between a reception of the second PDSCH and a reception ofthe second PDCCH. For example, the second PDCCH is a PDCCH addressed tothe C-RNTI and/or firstly received after or in response to the two-stepRA procedure being successfully complete. The second PDCCH may be aPDCCH indicating a DL or UL transmission (e.g., a new DL or ULtransmission) addressed to the C-RNTI.

In FIG. 33 , a wireless device may start an active time with a firsttime offset in response to transmitting the MsgA and stop the activetime in response to receiving the first PDSCH. For example, a durationof the active time comprises a second duration between a first time theMsgA is transmitted with the first time offset and a second time thefirst PDSCH is received. The first time offset may be predefined as afirst value (e.g., zero). For example, the first time offset may be areference symbol (e.g., first symbol or firstly located symbol in time)of a CORESET. For example, the CORESET is the earliest CORESET that isat least one or more symbols (e.g., at least one symbol) after a lastsymbol of a preamble transmission occasion of the preamble. For example,the CORESET is the earliest CORESET that is at least one or more symbols(e.g., at least one symbol) after a last symbol of a transport block(and/or MsgA) transmission occasion of the transport block (and/orMsgA).

In FIG. 33 , a wireless device may start an active time with a firsttime offset in response to transmitting the MsgA. The wireless devicemay determine the active time until the wireless device receives thesecond PDSCH (and/or may stop the active time in response to receivingthe second PDSCH). For example, a duration of the active time comprisesa second duration between a first time the MsgA is transmitted the firsttime offset and a second time the second PDSCH is received. The firsttime offset may be predefined as a first value (e.g., zero). Forexample, the first time offset may be a reference symbol (e.g., firstsymbol or firstly located symbol in time) of a CORESET. For example, theCORESET is the earliest CORESET that is at least one or more symbols(e.g., at least one symbol) after a last symbol of a preambletransmission occasion of the preamble. For example, the CORESET is theearliest CORESET that is at least one or more symbols (e.g., at leastone symbol) after a last symbol of a transport block (and/or MsgA)transmission occasion of the transport block (and/or MsgA).

In FIG. 33 , a wireless device may start an active time with a firsttime offset in response to transmitting the MsgA. The wireless devicemay determine, as the active time, a time until the wireless devicereceive the second PDCCH (and/or may stop the active time in response toreceiving the second PDCCH). For example, a duration of the active timecomprises a second duration between a first time the MsgA is transmittedthe first time offset and a second time the second PDCCH is received.The first time offset may be predefined as a first value (e.g., zero).For example, the first time offset may be a reference symbol (e.g.,first symbol or firstly located symbol in time) of a CORESET. Forexample, the CORESET is the earliest CORESET that is at least one ormore symbols (e.g., at least one symbol) after a last symbol of apreamble transmission occasion of the preamble. For example, the CORESETis the earliest CORESET that is at least one or more symbols (e.g., atleast one symbol) after a last symbol of a transport block (and/or MsgA)transmission occasion of the transport block (and/or MsgA). The wirelessdevice may (re)start, based on receiving the second PDCCH and/or basedon a DRX operation described in the specification, one or more firsttimers and/or stop one or more second timers. For example, the one ormore first timers comprise drx-HARQ-RTT-TimerDL (e.g., the second PDCCHcomprise a DL assignment). For example, the one or more first timerscomprise drx-HARQ-RTT-TimerUL (e.g., the second PDCCH comprise a ULgrant). For example, the one or more first timers comprisedrx-InactivityTimer (e.g., the second PDCCH indicating a newtransmission (DL or UL). The one or more second timers comprisedrx-RetransmissionTimerDL (e.g., the second PDCCH comprise a DLassignment). The one or more second timers comprisedrx-RetransmissionTimerUL (e.g., the second PDCCH comprise a UL grant).

FIG. 34 is an example of a DRX operation. The wireless device mayinitiate a two-step RA procedure performing. The two-step RA proceduremay be a contention-based two-step RA procedure. For example, for thecontention-based two-step RA procedure, a preamble transmitted by thewireless device via MsgA is selected by an MAC layer of the wirelessdevice among the one or more preambles assigned (or configured orallocated) for the contention-based two-step RA procedure. The two-stepRA procedure may be a contention-free two-step RA procedure. Forexample, for the contention-free two-step RA procedure, a preambletransmitted by the wireless device via MsgA is not selected by an MAClayer of the wireless device among the one or more preambles assigned(or configured or allocated) for the contention-based two-step RAprocedure. The wireless device may transmit a preamble and a transportblock as a transmission of an MsgA. The wireless device may start tomonitor a downlink control channel for a response of the MsgA. Thewireless device may monitor the downlink control channel based on aC-RNTI, e.g., if the transport block comprises the C-RNTI (e.g., C-RNTIMAC CE). The wireless device may monitor the downlink control channelbased on a msgB RNTI (or RA-RNTI), e.g., if the transport blockcomprises an RRC request message (e.g., CCCH SDU) (and/or the transportblock does not comprise the C-RNTI (e.g., C-RNTI MAC CE)). The wirelessdevice may receive a first PDCCH via the downlink control channel. Thewireless device may receive the first PDCCH during a msgB RAR windowstarting in response to transmitting the MsgA (or transport block of theMsgA). The first PDCCH (e.g., DCI) may indicate a first DL assignmentfor receiving a first PDSCH (e.g., MsgB1). The first PDCCH (e.g., DCI)may be addressed to the C-RNTI, e.g., if the wireless device transmitsthe C-RNTI via the MsgA. The first PDCCH (e.g., DCI) may be addressed tothe msgB RNTI (or RA-RNTI), e.g., if the wireless device transmit theRRC request message (e.g., CCCH SDU). The wireless device may receive,based on the first DL assignment, the first PDSCH. The first PDSCH maycomprise the MsgB1, a response of the MsgA. For example, the MsgB1comprise at least one of: a TA command, a UL grant, and/or a contentionresolution identifier. The wireless device may determine the two-step RAprocedure is successfully complete in response to receiving the MsgB1.The wireless device may determine the two-step RA procedure issuccessfully complete in response to receiving the first PDSCH (e.g.,comprising the MsgB1). The wireless device may identify the MsgB1 as theresponse of the MsgA from the first PDSCH (e.g., a MAC PDU) based onexample embodiments described in this specification (e.g., based on anRAPID and/or the contention resolution identifier). For example, thefirst PDSCH (e.g., comprising the MsgB1) comprises an indicator (e.g.,the first MsgB2 indication and/or the second MsgB2 indication). Thewireless device determines, based on the indicator, the MsgB2 is not inthe first PDSCH. The MsgB2 may further comprise a second DL assignment.The second DL assignment may indicate a DL scheduling informationrequired for receiving a second PDSCH (e.g., comprising the MsgB2). Thewireless device may receive, based on the second DL assignment, thesecond PDSCH (e.g., comprising the MsgB2). The wireless device mayattempt to receive, based on the second DL assignment, the second PDSCHbased on determining that the MsgB2 is not in the first PDSCH and/or theMsgB1 is a response of the MsgA. the second DL assignment may indicateone or more DL transmission parameters, e.g., a reception timing, areceiving frequency, a size of the PDSCH, and the like. The second PDSCHmay comprise the RRC message. For example, the RRC message may be one ofRRC (re)establishment message, RRC setup message, and/or RRC resumemessage. The wireless device may determine the two-step RA procedure issuccessfully complete in response to receiving the MsgB2. The wirelessdevice may determine the two-step RA procedure is successfully completein response to receiving the second PDSCH (e.g., comprising the MsgB2).The wireless device may stop the msgB RAR window in response toreceiving the first PDSCH. The wireless device may stop the msgB RARwindow in response to receiving the second PDSCH. The wireless devicemay start to monitor a downlink control channel based on a particularRNTI, e.g., after or in response to receiving the second PDSCH (e.g.,comprising the MsgB2). The particular RNTI may be a C-RNTI or TC-RNTI.The MsgB1 may comprise the particular RNTI. The wireless device mayreceive a second PDCCH via the downlink control channel after or inresponse to receiving the second PDSCH (e.g., comprising the MsgB2). Forexample, the second PDCCH is a PDCCH addressed to the C-RNTI and/orfirstly received after or in response to receiving the first PDSCH. Forexample, the wireless device receives no PDCCH addressed to the C-RNTIbetween a reception of the first PDSCH and a reception of the secondPDCCH. For example, the second PDCCH is a PDCCH addressed to the C-RNTIand/or firstly received after or in response to receiving the secondPDSCH. For example, the wireless device receives no PDCCH addressed tothe C-RNTI between a reception of the second PDSCH and a reception ofthe second PDCCH. For example, the second PDCCH is a PDCCH addressed tothe C-RNTI and/or firstly received after or in response to the two-stepRA procedure being successfully complete. The second PDCCH may be aPDCCH indicating a DL or UL transmission (e.g., a new DL or ULtransmission) addressed to the C-RNTI.

In FIG. 34 , a wireless device may start an active time with a firsttime offset in response to receiving the first PDCCH. The wirelessdevice may stop the active time in response to receiving the secondPDSCH. For example, a duration of the active time comprises a secondduration between a first time first PDCCH is received with the firsttime offset and a second time the second PDSCH is received. For example,the first time offset may be predefined as a first value (e.g., zero).For example, the first time offset may be a reference symbol (e.g.,first symbol or firstly located symbol in time) of a CORESET. Forexample, the CORESET is the earliest CORESET that is at least one ormore symbols (e.g., at least one symbol) after receiving the firstPDCCH. For example, the CORESET is the earliest CORESET comprising oneor more symbols where the first PDCCH is receive.

In FIG. 34 , a wireless device may start an active time with a firsttime offset in response to receiving the first PDCCH. The wirelessdevice may determine the active time until the wireless device receivesthe second PDCCH (and/or may stop the active time in response toreceiving the second PDCCH). For example, a duration of the active timecomprises a second duration between a first time first PDCCH is receivedwith the first time offset and a second time the second PDCCH isreceived. The first time offset may be predefined as a first value(e.g., zero). For example, the first time offset may be a referencesymbol (e.g., first symbol or firstly located symbol in time) of aCORESET. For example, the CORESET is the earliest CORESET that is atleast one or more symbols (e.g., at least one symbol) after receivingthe first PDCCH. For example, the CORESET is the earliest CORESETcomprising one or more symbols where the first PDCCH is receive. Thewireless device may (re)start, based on receiving the second PDCCHand/or based on a DRX operation described in the specification, one ormore first timers and/or stop one or more second timers. For example,the one or more first timers comprise drx-HARQ-RTT-TimerDL (e.g., thesecond PDCCH comprise a DL assignment). For example, the one or morefirst timers comprise drx-HARQ-RTT-TimerUL (e.g., the second PDCCHcomprise a UL grant). For example, the one or more first timers comprisedrx-InactivityTimer (e.g., the second PDCCH indicating a newtransmission (DL or UL). The one or more second timers comprisedrx-RetransmissionTimerDL (e.g., the second PDCCH comprise a DLassignment). The one or more second timers comprisedrx-RetransmissionTimerUL (e.g., the second PDCCH comprise a UL grant).

In FIG. 34 , a wireless device may start an active time in response toreceiving the first PDSCH. The wireless device may determine, as theactive time, a time until the wireless device receive the second PDSCH.For example, a duration of the active time comprises a second durationbetween a first time first PDSCH is received and a second time thesecond PDSCH is received.

In FIG. 34 , a wireless device may start an active time in response toreceiving the first PDSCH. The wireless device may start an active timein response to receiving the MsgB1 (and/or determining that the MsgB1 isa response of the MsgA based on example embodiment(s) described in thisspecification). The wireless device may start an active time in responseto receiving the MsgB1 (and/or determining, based on receiving theMsgB1, that the two-step RA procedure is successfully complete). Thewireless device may start an active time in response to receiving theMsgB1 (and/or determining, based on receiving the MsgB1, that areception of the response of the MsgA is successful). The wirelessdevice may determine, as the active time, a time until the wirelessdevice receive the second PDCCH. For example, a duration of the activetime comprises a second duration between a first time first PDSCH (e.g.,the MsgB1) is received and a second time the second PDCCH is received.The wireless device may (re)start, based on receiving the second PDCCHand/or based on a DRX operation described in the specification, one ormore first timers and/or stop one or more second timers. For example,the one or more first timers comprise drx-HARQ-RTT-TimerDL (e.g., thesecond PDCCH comprise a DL assignment). For example, the one or morefirst timers comprise drx-HARQ-RTT-TimerUL (e.g., the second PDCCHcomprise a UL grant). For example, the one or more first timers comprisedrx-InactivityTimer (e.g., the second PDCCH indicating a newtransmission (DL or UL). The one or more second timers comprisedrx-RetransmissionTimerDL (e.g., the second PDCCH comprise a DLassignment). The one or more second timers comprisedrx-RetransmissionTimerUL (e.g., the second PDCCH comprise a UL grant).

In FIG. 34 , a wireless device may start an active time in response toreceiving the second PDSCH. The wireless device may start an active timein response to receiving the MsgB2 (and/or determining that the MsgB2 isa response of the MsgA based on example embodiment(s) described in thisspecification). The wireless device may start an active time in responseto receiving the MsgB2 (and/or determining, based on receiving theMsgB2, that the two-step RA procedure is successfully complete). Thewireless device may start an active time in response to receiving theMsgB2 (and/or determining, based on receiving the MsgB2, that areception of the response of the MsgA is successful). The wirelessdevice may determine, as the active time, a time until the wirelessdevice receive the second PDCCH. For example, a duration of the activetime comprises a second duration between a first time second PDSCH isreceived and a second time the second PDCCH is received. The wirelessdevice may (re)start, based on receiving the second PDCCH and/or basedon a DRX operation described in the specification, one or more firsttimers and/or stop one or more second timers. For example, the one ormore first timers comprise drx-HARQ-RTT-TimerDL (e.g., the second PDCCHcomprise a DL assignment). For example, the one or more first timerscomprise drx-HARQ-RTT-TimerUL (e.g., the second PDCCH comprise a ULgrant). For example, the one or more first timers comprisedrx-InactivityTimer (e.g., the second PDCCH indicating a newtransmission (DL or UL). The one or more second timers comprisedrx-RetransmissionTimerDL (e.g., the second PDCCH comprise a DLassignment). The one or more second timers comprisedrx-RetransmissionTimerUL (e.g., the second PDCCH comprise a UL grant).

According an embodiment, a wireless device may transmit a first messagecomprising: a first preamble and a first transport block comprising awireless device identity. The wireless device may receive a firstresponse during a time interval starting in response to transmitting thefirst message. The wireless device may determine a portion of the timeinterval as an active time of a discontinuous reception operation inresponse to the first response comprising the wireless device identity.The wireless device may monitor (or start to monitor), based on theportion of the time interval, a control channel based on one or morenetwork identifiers used for the discontinuous reception operation. Thewireless device may transmit an uplink control signal in response to adecoding success of a second response received during the Active Time.For example, a second time interval may start in response to the firstresponse comprising the wireless device identity. For example, the timeinterval restarts in response to the first response comprising thewireless device identity. For example, the wireless device receives thesecond response within time interval. For example, the portion of theactive time starts in response to receiving the first response. Forexample, the first transport block further comprises a radio resourcecontrol message request. For example, the radio resource control messagerequest comprises at least one of: a radio resource control(re)establishment request; a radio resource control setup request;and/or a radio resource control resume request. For example, the secondresponse comprises a radio resource control message. For example, theradio resource control message comprises at least one of: a radioresource control (re)establishment message; a radio resource controlsetup message; and/or a radio resource control resume message. Forexample, the wireless device receives, based on a first networkidentifier, a first downlink control information, wherein the firstdownlink control information indicates a downlink assignment used forreceiving the first response. For example, the one or more networkidentifiers does not comprise the first network identifier. For example,the first network identifier is a random access network identifier usedfor a two-step random access procedure. For example, the one or morenetwork identifier comprises a cell network identifier. For example, thewireless device stops the first time interval in response to receivingthe first response. For example, the wireless device stops the firsttime interval in response to receiving the second response. For example,the first response further comprises a downlink assignment for receivingthe second response. For example, the wireless device receives, based onthe downlink assignment, the second response. For example, the wirelessdevice determines the end of the active time in response to receivingthe first response. For example, the wireless device determines the endof the active time in response to receiving the second response. Forexample, the wireless device determines the end of the active time inresponse to receiving a downlink control information scheduling thesecond response. For example, the wireless device transmits the firstmessage for a two-step random access procedure. For example, thetwo-step random access procedure is a contention-based two-step randomaccess procedure. For example, the two-step random access procedure is acontention-free two-step random access procedure.

According to an example embodiment, a wireless device may transmit afirst message comprising a first preamble and a first transport blockcomprising a wireless device identity. The wireless device may receive afirst response during a time interval starting in response totransmitting the first message. the wireless device may start an activetime of a discontinuous reception operation in response to the firstresponse indicating the wireless device identity. The wireless devicemay monitor (or start to monitor), based on the active time, a controlchannel based on one or more network identifiers used for thediscontinuous reception operation. The wireless device may transmit anuplink control signal in response to a decoding success of a secondresponse received during the Active Time.

According to an example embodiment, a wireless device may transmit afirst message comprising a first preamble and/or a first transport blockcomprising a wireless device identity. The wireless device may receive afirst response of the first message during a time interval starting inresponse to transmitting the first message. The wireless device mayreceive, based on a downlink assignment indicated by the first response,a second response of the first message. The wireless device may start anactive time of a discontinuous reception operation in response toreceiving the second response. The wireless device may start to monitor,based on the active time, a control channel based on one or more networkidentifiers used for the discontinuous reception operation. For example,the wireless device may determine to stop the first time interval inresponse to receiving the first response. For example, the wirelessdevice may determine to stop the first time interval in response toreceiving the second response.

According to an example embodiment, a wireless device may transmit afirst message comprising a first preamble and/or a first transport blockcomprising a wireless device identity. The wireless device may, inresponse to transmitting the first message, start a time interval. Thewireless device may, in response to transmitting the first message,start an active time of a discontinuous reception operation. Thewireless device may start to monitor, during the active time, a controlchannel based on one or more network identifiers used for thediscontinuous reception operation. The wireless device may receiveduring the time interval, a first response indicating the wirelessdevice identity.

FIG. 35 is a flow diagram as per an aspect of an example embodiment ofthe present disclosure. At 3510, a wireless device may transmit amessage comprising a preamble and a transport block. The transport blockmay indicate a wireless device identity of the wireless device. Thetransport block may be transmitted via a transmission occasion. At 3520,the wireless device may determine that a discontinuous reception (DRX)operation of the wireless device is in a DRX active time based on a timewindow running. The time window may start at a first symbol of a controlresource set of the wireless device that is at least one symbol afterthe transmission occasion. At 3530, the wireless device may receive, viaone or more downlink control channels, a response to the message. Thewireless device may receive the response based on based on thedetermination that the DRX operation is in the DRX active time. At 3540,the wireless device may stop monitoring the one or more downlink controlchannels. The wireless device may stop the monitoring based on adetermination that the DRX operation is not in the DRX active time inresponse to receiving the response.

According to an example embodiment, the wireless device may transmit themessage is for a two-step random access procedure. The wireless devicemay receive DRX configuration parameters configuring the DRX operation.The wireless device may transmit the preamble via a physical randomaccess channel (PRACH) transmission occasion. The transmission occasionmay be a physical uplink shared channel (PUSCH) transmission occasion.The wireless device may monitor, for the response, the one or moredownlink control channels using a Message B radio network temporaryidentifier (MSGB-RNTI). The wireless device may determine the MSGB-RNTIbased on radio resource parameters of the PRACH transmission occasionand/or the PUSCH transmission occasion. The wireless device may monitor,based on the determination that the DRX operation is in the DRX activetime, the one or more downlink control channels using one or morenetwork identifiers used for the DRX operation. The wireless device maystop the time window in response to receiving the response. Thedetermination that the DRX operation is not in the DRX active time maybe in response to stopping the time window. The DRX operation may be inthe DRX active time while the time window is running. The transportblock may comprise a cell radio network temporary identifier (C-RNTI)medium access control control element (MAC CE) indicating the C-RNTI ofthe wireless device. The C-RNTI may indicate the wireless deviceidentity. The wireless device may monitor, for the response and based onthe transport block comprising the C-RNTI MAC CE, the one or moredownlink control channels using the C-RNTI. The response may be downlinkcontrol information (DCI) addressed to the C-RNTI. The wireless devicemay determine that the two-step random access procedure completessuccessfully in response to the response being the DCI addressed to theC-RNTI. The DCI may comprise a grant for a transmission. The grant maybe an uplink grant. The grant may be a downlink assignment. The wirelessdevice may start a DRX inactivity timer in response to the transmissionbeing a new transmission. The wireless device may determine that the DRXoperation is in the active time while the DRX inactivity timer isrunning. The wireless device may receive, during the active time, asecond DCI comprising a second grant for a retransmission of thetransmission. The wireless device may start, in response to the secondDCI, a DRX hybrid automatic repeat request (HARQ) round trip time (RTT)timer. The wireless device may start a DRX retransmission timer inresponse to an expiry of the DRX HARQ RTT timer, wherein the DRXoperation is in the DRX active time based on the DRX retransmissiontimer running.

A wireless device may transmit a message comprising a preamble and atransport block. The transport block may indicate a wireless deviceidentity of the wireless device. The transport block may be transmittedvia a transmission occasion. The wireless device may determine that adiscontinuous reception (DRX) operation of the wireless device is in aDRX active time based on a time window running, wherein the time windowstarts at a first symbol of a control resource set of the wirelessdevice that is at least one symbol after the transmission occasion. Thewireless device may receive, via one or more downlink control channelsand based on the determining, a response to the message. The DRXoperation may not be in the DRX active time in response to the response.

According to an example embodiment, the wireless device may stopmonitoring the one or more downlink control channels based on the DRXoperation being not in the DRX active time. The wireless device may stopthe time window in response to receiving the response. The determinationthat the DRX operation is not in the DRX active time may be in responseto stopping the time window. The DRX operation may be in the DRX activetime while the time window is running.

A wireless device may transmit a message comprising a preamble and atransport block. The wireless device may receive, during a discontinuousreception (DRX) active time, a response to the message. The DRX activetime may be based on a time window that starts at least one symbol aftera transmission occasion of the transport block.

According to an example embodiment, the transport block may indicate awireless device identity. The transport block may be transmitted via atransmission occasion. The wireless device may determine that the DRXoperation of the wireless device is in the DRX active time based on thetime window running. The wireless device may stop monitoring one or moredownlink control channels based on a determination that the DRXoperation is not in the DRX active time in response to receiving theresponse. The time window may start from a first symbol of a controlresource set of the wireless device that is the at least one symbolafter the transmission occasion.

A wireless device may receive, during a discontinuous reception (DRX)active time, a response to a message. The message may comprise apreamble and a transport block. The DRX active time may be determinedbased on a time window that starts at least one symbol after atransmission occasion of the transport block.

According to an example embodiment, the wireless device may transmit themessage comprising the preamble the transport block. The wireless devicemay transmit the message is for a two-step random access procedure. Thetransport block may be transmitted via a transmission occasion. The timewindow may start from a first symbol of a control resource set of thewireless device that is the at least one symbol after the transmissionoccasion. The wireless device may determine that the DRX operation ofthe wireless device is in the DRX active time based on the time windowrunning. The wireless device may stop monitoring the one or moredownlink control channels based on a determination that the DRXoperation is not in the DRX active time in response to receiving theresponse. The wireless device may monitor, for the response, the one ormore downlink control channels using a Message B radio network temporaryidentifier (MSGB-RNTI). The wireless device may monitor, based on thedetermination that the DRX operation is in the DRX active time, the oneor more downlink control channels using one or more network identifiersused for the DRX operation. The wireless device may stop the time windowin response to receiving the response. The DRX operation may be in theDRX active time while the time window is running. The transport blockmay comprise a cell radio network temporary identifier (C-RNTI) mediumaccess control control element (MAC CE) that indicates the C-RNTI of thewireless device. The C-RNTI may indicate the wireless device identity.The wireless device may monitor, for the response and based on thetransport block comprising the C-RNTI MAC CE, the one or more downlinkcontrol channels using the C-RNTI. The response may be downlink controlinformation (DCI) addressed to the C-RNTI. The wireless device maydetermine that the two-step random access procedure completessuccessfully in response to the response being the DCI addressed to theC-RNTI. The DCI may comprise a grant for a transmission. The grant maybe an uplink grant. The grant may be a downlink assignment. The wirelessdevice may start a DRX inactivity timer in response to the transmissionbeing a new transmission. The wireless device may determine that the DRXoperation is in the active time while the DRX inactivity timer isrunning. The wireless device may receive, during the active time, asecond DCI comprising a second grant for a retransmission of thetransmission. The wireless device may start, in response to the secondDCI, a DRX hybrid automatic repeat request (HARQ) round trip time (RTT)timer. The wireless device may start a DRX retransmission timer inresponse to an expiry of the DRX HARQ RTT timer. The DRX operation maybe in the DRX active time based on the DRX retransmission timer running.

FIG. 36 is a flow diagram as per an aspect of an example embodiment ofthe present disclosure. At 3610, a base station may receive, from awireless device, a message comprising a preamble and a transport block.The transport block may indicate a wireless device identity. Thetransport block may be transmitted via a transmission occasion. At 3620,the base station may determine that a discontinuous reception (DRX)operation of the wireless device is in a DRX active time based on a timewindow running. The time window may start at a first symbol of a controlresource set of the wireless device that is at least one symbol afterthe transmission occasion. At 3630, the base station may transmit, viaone or more downlink control channels and based on the determinationthat the DRX operation is in the DRX active time, a response to themessage. The DRX operation may not be in the DRX active time in responseto transmitting the response.

According to an example embodiment, the message may be for a two-steprandom access procedure. The base station may transmit DRX configurationparameters configuring the DRX operation. The base station may receivethe preamble via a physical random access channel (PRACH) transmissionoccasion. The transmission occasion may be a physical uplink sharedchannel (PUSCH) transmission occasion. The base station may determinethat the wireless device monitors, for the response, the one or moredownlink control channels using a Message B radio network temporaryidentifier (MSGB-RNTI). The base station may determine that the wirelessdevice monitors, based on the determination that the DRX operation is inthe DRX active time, the one or more downlink control channels using oneor more network identifiers used for the DRX operation. The base stationmay stop the time window in response to transmitting the response. Thedetermination that the DRX operation is not in the DRX active time maybe in response to stopping the time window. The DRX operation may be inthe DRX active time while the time window is running. The transportblock may comprise a cell radio network temporary identifier (C-RNTI)medium access control control element (MAC CE) indicating the C-RNTI ofthe wireless device. The base station may determine that the wirelessdevice monitors, for the response and based on the transport blockcomprising the C-RNTI MAC CE, the one or more downlink control channelsusing the C-RNTI. The C-RNTI may indicate the wireless device identity.The response may be downlink control information (DCI) addressed to theC-RNTI. The base station may determine that the two-step random accessprocedure completes successfully in response to the response being theDCI addressed to the C-RNTI. The DCI may comprise a grant for atransmission. The grant may be an uplink grant. The grant may be adownlink assignment. The base station may start a DRX inactivity timerin response to the transmission being a new transmission. The basestation may determine that the DRX operation is in the active time whilethe DRX inactivity timer is running. The base station may transmit,during the active time, a second DCI comprising a second grant for aretransmission of the transmission. The base station may start, inresponse to the second DCI, a DRX hybrid automatic repeat request (HARQ)round trip time (RTT) timer. The base station may start a DRXretransmission timer in response to an expiry of the DRX HARQ RTT timer.The DRX operation may be in the DRX active time based on the DRXretransmission timer running.

A base station may transmit, to a wireless device and during adiscontinuous reception (DRX) active time, a response to a message thatcomprises a preamble and a transport block, wherein the DRX active timeis determined based on a time window that starts at least one symbolafter a transmission occasion of the transport block.

According to an example embodiment, the base station may receive themessage comprising the preamble the transport block. The base stationmay receive the message for a two-step random access procedure. The basestation may receive the transport block via a transmission occasion. Thetime window may start from a first symbol of a control resource set ofthe wireless device that is the at least one symbol after thetransmission occasion. The base station may determine that the DRXoperation of the wireless device is in the DRX active time based on thetime window running. The DRX operation may not be in the DRX active timein response to receiving the response. The base station may determinethat the wireless device monitors, for the response, the one or moredownlink control channels using a Message B radio network temporaryidentifier (MSGB-RNTI). The base station may determine that the wirelessdevice monitors, based on the determining, the one or more downlinkcontrol channels using one or more network identifiers used for the DRXoperation. The base station may stop the time window in response totransmitting the response. The DRX operation may be in the DRX activetime while the time window is running. The transport block may comprisea cell radio network temporary identifier (C-RNTI) medium access controlcontrol element (MAC CE) indicating the C-RNTI of the wireless device.The C-RNTI may indicate the wireless device identity. The base stationmay determine that the wireless device monitors, for the response andbased on the transport block comprising the C-RNTI MAC CE, the one ormore downlink control channels using the C-RNTI. The response may bedownlink control information (DCI) addressed to the C-RNTI. The basestation may determine that the two-step random access procedurecompletes successfully in response to the response being the DCIaddressed to the C-RNTI. The DCI may comprise a grant for atransmission. The grant may be an uplink grant. The grant may be adownlink assignment. The base station may start a DRX inactivity timerin response to the transmission being a new transmission. The basestation may determine that the DRX operation is in the active time whilethe DRX inactivity timer is running. The base station may transmit,during the active time, a second DCI comprising a second grant for aretransmission of the transmission. The base station may start, inresponse to the second DCI, a DRX hybrid automatic repeat request (HARQ)round trip time (RTT) timer. The base station may start a DRXretransmission timer in response to an expiry of the DRX HARQ RTT timer.The DRX operation may be in the DRX active time based on the DRXretransmission timer running.

What is claimed is:
 1. A method comprising: receiving, by a wirelessdevice, one or more configuration parameters for a two-step randomaccess (RA) procedure; transmitting, based on the one or moreconfiguration parameters, a message, for the two-step RA procedure,comprising a preamble and a transport block; and receiving, during adiscontinuous reception (DRX) active time of a DRX operation of thewireless device, a response to the message, wherein: the DRX active timeis based on a time window for receiving the response to the message, andthe time window starts at least one symbol after a transmission occasionof the transport block.
 2. The method of claim 1, wherein the transportblock indicates a wireless device identity.
 3. The method of claim 1,further comprising determining the DRX operation is in the DRX activetime based on the time window running.
 4. The method of claim 3, furthercomprising stopping the time window in response to receiving theresponse.
 5. The method of claim 1, wherein the time window starts froma first symbol of a control resource set of the wireless device that isthe at least one symbol after the transmission occasion.
 6. The methodof claim 1, wherein the transport block comprises a cell radio networktemporary identifier (C-RNTI) medium access control control element (MACCE) indicating a C-RNTI of the wireless device.
 7. The method of claim6, wherein the C-RNTI indicates an identity of the wireless device. 8.The method of claim 7, further comprising monitoring, for the responseand based on the transport block comprising the C-RNTI MAC CE, one ormore downlink control channels using the C-RNTI.
 9. The method of claim9, wherein the response is a downlink control information (DCI)addressed to the C-RNTI.
 10. The method of claim 1, further comprisingmonitoring one or more downlink control channels for the response usinga radio network temporary identifier.
 11. A wireless device comprising:one or more processors; and memory storing instructions that, whenexecuted by the one or more processors, causes the wireless device to:receive one or more configuration parameters for a two-step randomaccess channel (RACH) procedure; transmit, based on the configurationparameters, a message, for the two-step RACH, comprising a preamble anda transport block; and receive, during a discontinuous reception (DRX)active time of a DRX operation of the wireless device, a response to themessage, wherein: the DRX active time is based on a time window forreceiving the response to the message, and the time window starts atleast one symbol after a transmission occasion of the transport block.12. The wireless device of claim 11, wherein the transport blockindicates a wireless device identity.
 13. The wireless device of claim11, further comprising determining the DRX operation is in the DRXactive time based on the time window running.
 14. The wireless device ofclaim 13, further comprising stopping the time window in response toreceiving the response.
 15. The wireless device of claim 11, wherein thetime window starts from a first symbol of a control resource set of thewireless device that is the at least one symbol after the transmissionoccasion.
 16. The wireless device of claim 11, wherein the transportblock comprises a cell radio network temporary identifier (C-RNTI)medium access control control element (MAC CE) indicating a C-RNTI ofthe wireless device.
 17. The wireless device of claim 16, wherein theC-RNTI indicates an identity of the wireless device.
 18. The wirelessdevice of claim 17, further comprising monitoring, for the response andbased on the transport block comprising the C-RNTI MAC CE, one or moredownlink control channels using the C-RNTI.
 19. The wireless device ofclaim 19, wherein the response is a downlink control information (DCI)addressed to the C-RNTI.
 20. A base station comprising: one or moreprocessors; and memory storing instructions that, when executed by theone or more processors, causes the base station to: transmit one or moreconfiguration parameters for a two-step random access channel (RACH)procedure; receive, based on the configuration parameters, a message,for the two-step RACH, comprising a preamble and a transport block; andtransmit, during a discontinuous reception (DRX) active time of a DRXoperation of the wireless device, a response to the message, wherein:the DRX active time is based on a time window for receiving the responseto the message, and the time window starts at least one symbol after atransmission occasion of the transport block.